Question: what does it mean when you have cramps under your belly?
Answer: Muscle strain. Overworking your abdominal muscles could cause them to spasm. ... 
Dehydration. ... 
Gas. ... 
Inflammatory bowel disease. ... 
Irritable bowel syndrome. ... 
Gastritis and gastroenteritis. ... 
Infectious colitis. ... 
Ischemic enteritis and colitis.