More than an ache. More than a stomach ache colitis - either ulcerative colitis or crohn's colitis are diseases of the colon of unknown origin. The associated inflammation causes ulcers in the colon which can bleed, cause diarrhea and pain. Long standing disease is associated with cancer of the colon. A physician specializing in the diseases can help. Medicines do work, but surgery can be needed. Peter wilk, md.