Irritable Bowel Syndrome (IBS): This is often the most common cause of gas pain in the abdomen, characterized by recurrent abdominal pain associated with a change in bowel habits, such as diarrhea or constipation, without any visible signs of damage or disease in the digestive tract.

Functional Dyspepsia: A term for recurring signs and symptoms of indigestion that have no obvious cause. Symptoms can vary but often include pain or discomfort in the upper abdomen.
Lactose Intolerance: The inability to digest lactose, a sugar found in milk and other dairy products, leading to bloating, gas, and abdominal pain after consuming these products.
Fructose Malabsorption: Similar to lactose intolerance, this condition involves the poor absorption of fructose, a sugar found in many fruits and some vegetables, leading to gas, bloating, and abdominal pain.
Small Intestine Bacterial Overgrowth (SIBO): A condition where there is an abnormal increase in the bacteria that inhabit the small intestine, leading to bloating, gas, and abdominal pain.

Appendicitis: Although less common, appendicitis can present with abdominal pain that may initially be diffuse or around the navel and then localize to the lower right abdomen. It's a medical emergency requiring prompt surgical intervention.
Intestinal Obstruction: A blockage that prevents the normal flow of the products of digestion, including food, fluid, and gas, which can lead to severe abdominal pain, vomiting, and constipation.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic inflammation of the GI tract, leading to abdominal pain, diarrhea, weight loss, and fatigue.
Gallbladder Disease: Gallstones or inflammation of the gallbladder can cause severe abdominal pain, often in the upper right or middle abdomen, which may radiate to the back or right shoulder.

Celiac Disease: An autoimmune disorder where the ingestion of gluten leads to damage in the small intestine, causing abdominal pain, diarrhea, fatigue, and weight loss.
Gastroparesis: A condition where the stomach takes too long to empty its contents, leading to nausea, vomiting, feeling full after eating only a small amount of food, and abdominal bloating.
Eosinophilic Gastroenteritis: A rare condition characterized by the presence of eosinophils in the gastrointestinal tract, leading to abdominal pain, nausea, vomiting, and diarrhea.
Abdominal Angina: A condition caused by reduced blood flow to the intestines, leading to chronic abdominal pain after eating, and weight loss.