Why Does Your Stomach Hurt? 15 Common Causes Explained

Tummy Trouble: What Stomach Pain Is Trying to Tell You

Stomach pain, clinically called abdominal pain, refers to any discomfort felt between the chest and the pelvis. It can originate from the stomach itself, the intestines, the liver, the gallbladder, the pancreas, or reproductive organs — all of which share the abdominal cavity.

Abdominal pain is one of the most common reasons people visit a doctor, accounting for approximately 5–10% of all emergency department visits globally. The pain may be:

• Acute — sudden onset, lasting hours to days
• Chronic — recurring over weeks, months, or longer
• Localised — concentrated in one area
• Diffuse — spread across the entire abdomen

Identifying the type and location of pain is the first step. Pain in the upper centre of the abdomen often points to the stomach or pancreas. Pain in the lower right may suggest appendicitis. Lower abdominal cramping frequently involves the intestines or reproductive organs.

1. Gastritis: When the Stomach Lining Becomes Inflamed

Gastritis is the inflammation of the stomach lining, typically causing a burning or gnawing pain in the upper abdomen.

The stomach lining produces a mucus layer that protects it from digestive acid. When that layer is damaged or thinned, stomach acid irritates the exposed tissue, causing inflammation. This is the core mechanism behind gastritis.

Common causes of gastritis include:

• Helicobacter pylori (H. pylori) bacterial infection — present in roughly 44% of the global population
• Regular use of NSAIDs such as ibuprofen or aspirin
• Excessive alcohol consumption
• Prolonged stress
• Autoimmune conditions (less common)

Symptoms to look for:

• Burning pain or discomfort in the upper abdomen, often worse when the stomach is empty
• Nausea or vomiting
• Feeling of fullness after eating small amounts
• Indigestion or bloating

Gastritis can be acute (short-term, triggered by a specific cause) or chronic (ongoing, typically linked to H. pylori or long-term NSAID use). Mool Health notes that untreated chronic gastritis can increase the risk of peptic ulcers and, in rare cases, stomach cancer.

2. Peptic Ulcer: Open Sores in the Stomach or Small Intestine

A peptic ulcer is an open sore that develops on the inner lining of the stomach (gastric ulcer) or the upper section of the small intestine (duodenal ulcer).

Peptic ulcers form when the balance between stomach acid and the protective mucus lining breaks down. H. pylori infection and NSAID overuse are responsible for the vast majority of cases.

Key symptoms include:

• A burning or dull aching pain in the centre or upper abdomen
• Pain that improves temporarily after eating or taking antacids in some cases
• Pain that worsens after eating in others
• Bloating or nausea
• Dark or tarry stools
• Vomiting blood in severe cases

Peptic ulcers do not always cause obvious symptoms. Untreated ulcers can lead to internal bleeding, perforation, or obstruction — all medical emergencies.

Treatment typically involves antibiotics when H. pylori is present, proton pump inhibitors to reduce acid, and addressing contributing medicines or lifestyle factors.

3. Stomach Virus: Viral Gastroenteritis and Gut Inflammation

A stomach virus — medically known as viral gastroenteritis — is an infection of the digestive tract caused by viruses such as norovirus or rotavirus.

Viral gastroenteritis inflames the lining of the stomach and intestines, disrupting normal fluid absorption and causing rapid onset of symptoms.

Typical symptoms include:

• Sudden cramping abdominal pain
• Nausea and vomiting
• Watery diarrhoea
• Low-grade fever
• Muscle aches and fatigue

The infection is highly contagious and can spread through contaminated food, water, or contact with an infected person.

What to do:

1. Stay hydrated with water or oral rehydration solution
2. Avoid heavy or difficult-to-digest foods while symptoms are active
3. Rest and allow the body to recover
4. Seek care if symptoms persist, blood appears in stool or vomit, or dehydration develops

4. Food Poisoning: When Contaminated Food Triggers Sudden Stomach Pain

Food poisoning is an illness caused by eating food contaminated with bacteria, viruses, parasites, or their toxins. It is one of the common causes of sudden stomach pain.

The mechanism varies by pathogen. Bacterial toxins can trigger inflammation in the digestive tract within hours of ingestion, while other infections can take longer to cause symptoms.

Food poisoning commonly causes:

• Sudden abdominal cramps
• Nausea or vomiting
• Diarrhoea
• Fever or chills
• Weakness or dizziness

Risk factors include:

• Undercooked meat, eggs, or seafood
• Unpasteurised foods
• Improperly stored leftovers
• Cross-contamination during food preparation

5. Irritable Bowel Syndrome: Chronic Gut Sensitivity Without Structural Damage

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterised by recurring abdominal pain linked to changes in bowel habits without visible structural damage to the digestive tract.

The main subtypes of IBS are:

Common symptoms include:

• Cramping or aching abdominal pain
• Bloating and excess gas
• Mucus in stool
• Urgency to use the toilet
• Feeling of incomplete evacuation

The exact cause of IBS is not fully understood. Gut-brain signalling, altered bowel movement, increased digestive sensitivity, food triggers, and stress can all influence symptoms.

6. Lactose Intolerance: When the Body Cannot Digest Dairy Properly

Lactose intolerance is the inability to fully digest lactose — the natural sugar found in milk and dairy products — due to insufficient production of the enzyme lactase in the small intestine.

When lactase levels are low, undigested lactose passes into the large intestine, where bacteria ferment it. This process produces gas and draws water into the bowel.

Symptoms can include:

• Bloating and abdominal cramps
• Excess gas
• Diarrhoea or loose stools
• Nausea

Lactose intolerance should not be confused with a milk allergy. Lactose intolerance is a digestive problem, while a food allergy involves the immune system.

7. Pelvic Inflammatory Disease: Infection-Driven Lower Abdominal Pain in Women

Pelvic inflammatory disease (PID) is an infection of the female reproductive organs, including the uterus, fallopian tubes, and ovaries.

PID causes lower abdominal or pelvic pain because infection leads to inflammation in reproductive tissues.

Symptoms of PID include:

• Lower abdominal or pelvic pain
• Unusual vaginal discharge
• Pain during sex or urination
• Irregular or heavy bleeding
• Fever
• Nausea or vomiting

8. Food Allergy: When the Immune System Overreacts to What You Eat

A food allergy is an immune-mediated reaction to a specific food protein, where the body identifies a normally harmless substance as a threat.

Unlike food intolerance, food allergy activates the immune system and can affect the digestive tract, skin, breathing, and circulation.

Gastrointestinal symptoms can include:

• Stomach cramps
• Nausea
• Vomiting
• Diarrhoea
• Tingling or swelling around the mouth

Common allergens include peanuts, tree nuts, shellfish, fish, milk, eggs, wheat, and soy.

9. Appendicitis: A Medical Emergency Starting as Stomach Pain

Appendicitis is inflammation of the appendix and is an important cause of acute abdominal pain requiring urgent medical assessment.

Appendicitis often begins when the appendix becomes blocked, leading to inflammation and increasing pressure.

Classic symptom progression includes:

1. Dull pain around the navel
2. Pain shifting towards the lower-right abdomen
3. Increasing pain intensity
4. Nausea or vomiting
5. Loss of appetite
6. Fever

Warning signs of rupture can include:

• Rapidly worsening abdominal pain
• High fever
• A rigid abdomen
• Rapid heart rate

10. Gallbladder Attack: Intense Upper Abdominal Pain from Gallstones

A gallbladder attack, also called biliary colic, occurs when gallstones block the normal flow of bile from the gallbladder.

The gallbladder stores bile — a digestive fluid produced by the liver — and releases it when you eat, particularly after fatty meals. When a stone blocks bile flow, pressure and gallbladder contraction can produce sudden, intense pain.

Symptoms can include:

• Sudden, intense pain in the upper-right or upper-centre abdomen
• Pain radiating to the right shoulder blade or back
• Nausea and vomiting
• Symptoms after fatty meals
• Fever or chills if infection develops
• Jaundice if the bile duct becomes blocked

Dietary management may help reduce attacks in some people, but established symptomatic gallstones often require medical treatment and may require laparoscopic cholecystectomy, which is surgical removal of the gallbladder.

11. Acid Reflux: When Stomach Acid Moves Upwards

acid reflux occurs when stomach contents move backwards into the oesophagus. This can cause a burning sensation in the chest or upper abdomen and may be mistaken for stomach pain.

Common symptoms include:

• Burning discomfort behind the breastbone
• Upper abdominal pain
• Sour or bitter taste in the mouth
• Frequent belching
• Symptoms after large meals
• Worsening discomfort when lying down

Eating smaller meals, avoiding lying down immediately after eating, and identifying personal trigger foods may help reduce reflux symptoms.

12. Constipation: Abdominal Pain From Slow Bowel Movement

Constipation occurs when bowel movements become infrequent, difficult, or incomplete. Stool that remains in the colon for longer periods becomes harder and more difficult to pass.

The build-up of stool and gas can cause cramping, pressure, bloating, and lower abdominal discomfort.

Common signs include:

• Hard or dry stools
• Straining during bowel movements
• Fewer bowel movements than usual
• Feeling of incomplete evacuation
• Abdominal bloating or discomfort

Adequate hydration, gradual fibre intake, regular physical activity, and a consistent bowel routine can help many people.

13. Kidney Stones: Severe Pain That Can Feel Like Stomach Pain

Kidney stones are hard mineral deposits that form inside the kidneys. Pain develops when a stone moves into the urinary tract.

Although kidney stones originate outside the digestive tract, pain can spread towards the abdomen or groin and may be mistaken for stomach pain.

Typical symptoms include:

• Severe pain in the side or back
• Pain radiating towards the lower abdomen or groin
• Pain that comes in waves
• Nausea or vomiting
• Blood in urine
• Frequent or painful urination

14. Pancreatitis: Inflammation of the Pancreas

Pancreatitis is inflammation of the pancreas, an organ involved in digestion and blood sugar regulation.

Acute pancreatitis can cause severe upper abdominal pain that may spread towards the back. Symptoms can become worse after eating.

Symptoms may include:

• Severe upper abdominal pain
• Pain radiating towards the back
• Nausea and vomiting
• Abdominal tenderness
• Fever
• Rapid pulse in severe cases

Gallstones and heavy alcohol use are among the recognised causes of pancreatitis, although medicines, metabolic conditions, and other medical problems can also contribute.

15. Menstrual Cramps: Lower Abdominal Pain During Periods

Menstrual cramps, medically called dysmenorrhoea, occur when the uterus contracts during menstruation.

These contractions are influenced by prostaglandins and may cause cramping pain in the lower abdomen.

Symptoms can include:

• Lower abdominal cramps
• Lower back pain
• Pain spreading towards the thighs
• Nausea
• Loose stools
• Headache or fatigue

Mild or moderate menstrual cramps are common. However, severe pain that regularly interferes with daily activity can sometimes be associated with conditions such as endometriosis, adenomyosis, fibroids, or other pelvic disorders.

How the Location of Stomach Pain Can Help Identify the Cause

The location of abdominal pain can provide clues about which organs or systems may be involved. However, pain location alone cannot confirm a diagnosis.

What Can You Do for Mild Stomach Pain?

For mild abdominal discomfort without red-flag symptoms, simple supportive measures may help depending on the likely cause.

1. Drink adequate water
2. Eat smaller, simpler meals temporarily
3. Avoid foods that clearly trigger symptoms
4. Avoid lying down immediately after meals
5. Use comfortable warmth for mild cramping
6. Take a gentle walk if gas or constipation may be contributing
7. Track foods, bowel movements, and symptoms
8. Get adequate rest

Home care should always be matched to the likely cause. A remedy that helps gas or mild indigestion may not be suitable for appendicitis, gallstones, pancreatitis, ulcers, or other medical conditions.

When Should You See a Doctor for Stomach Pain?

Seek medical advice when abdominal pain is persistent, recurring, unexplained, or progressively worsening.

Seek urgent medical care if you experience:

• Sudden or severe abdominal pain
• A rigid or significantly swollen abdomen
• Vomiting blood
• Black or bloody stools
• Persistent vomiting
• High fever with abdominal pain
• Jaundice
• Severe dehydration
• Chest pain or difficulty breathing
• Fainting or severe weakness
• Severe lower-right abdominal pain
• Severe abdominal pain during pregnancy
• Pain that continues to worsen instead of improving