Stigmaoscopy showed patchy inflamation in splendic flexure but bloods scan xray all clear can this be from constipation or does it have to be colitis?

Colitis: Colitis is a nonspecific term referring to inflammation of the colon. It can have many causes, including infection, auto-immune (ulcerative colitis or Crohn's disease), low blood flow (ischemia), and constipation to name a few. Ask your gastroenterologist what their opinion is, and what should be done. Above all, don't worry - it will be OK. Hope this helps!