Stomach Pain: Common Causes, Red Flags & When to See a Doctor

Abdominal pain is a nonspecific symptom with a vast differential. Pattern recognition (location, quality, timing, associated features) guides diagnosis.

Common Benign / Functional Causes

• Gas/bloating: Distension, crampy, relieved by passage of flatus/stool. Dietary triggers (FODMAPs, carbonation).
• Constipation: Infrequent/hard stools, straining; pain often LLQ/suprapubic.
• Diarrhea (infectious, IBS-D, food intolerance): Cramping, urgency, loose stools.
• Functional dyspepsia: Epigastric pain/burning, early satiety, postprandial fullness; normal endoscopy.
• GERD: Retrosternal burning, regurgitation; worse supine/postprandial.

Organic / Structural Causes

Condition	Typical Location	Key Features
Peptic ulcer (H. pylori / NSAID)	Epigastric	Gnawing/burning; relates to meals (duodenal: relief; gastric: aggravation)
Biliary colic / cholecystitis	RUQ → scapula	Postprandial (fatty), colicky → constant; Murphy's sign if inflamed
Pancreatitis	Epigastric → back	Severe, constant; nausea/vomiting; ↑ lipase 3× ULN
Appendicitis	Periumbilical → RLQ	Migrating pain, anorexia, fever, rebound tenderness
Diverticulitis	LLQ	Constant, fever, leukocytosis; CT confirms
IBD (Crohn's, UC)	Variable	Chronic diarrhea, blood, weight loss, extraintestinal manifestations
Renal colic	Flank → groin	Excruciating, wave-like; hematuria
Gynecologic (ovarian cyst, endometriosis, PID, ectopic)	Pelvic/LLQ/RLQ	Cyclic or acute; vaginal bleeding/discharge; β-hCG mandatory

Red Flags → Urgent Evaluation

• Severe, unremitting pain >6 hours
• Fever + abdominal pain
• Hematemesis, melena, hematochezia
• Jaundice, tea-colored urine
• Pregnancy + pain (rule out ectopic)
• Signs of peritonitis (rigidity, guarding, absent bowel sounds)
• Unexplained weight loss, night sweats

Do not self-diagnose. A targeted history, exam, and selective testing (CBC, CMP, lipase, urinalysis, β-hCG, imaging) usually identify the cause.