Developed diverticulitis following colonoscopy. first time ever had it. colon now messed up. chance of diverticulitis happening again?

Yes possible: Incidence of developing episode of diverticulitis attach is very low after colonoscopy that is the chance one has to take to detect unknown malignancy. Some groups even advocating the procedure in presence of acute attach during hospitalization. Your next attach will happen is unpredictable depends on extent, diet, bowel habits associated diseases etc.

Close observation: One risk associated with an elective colonoscopy is a perforation. A plain xray of your abdomen when symptoms start after procedure can help diagnose. It would be difficult to tell the difference from diverticulitis. Recurrance risk will also depend on status of diverticular disease.