Having a little pain/discomfort in upper left quadrant of abdomen. Had right side of colon removed 3 yrs ago. Pain has been there 3 days; not severe, but nagging. Is about belt level.

Was . Was your right colectomy due to cancer or diverticulitis? Either way: the concern is recurrence of either disease--which could be serious. An abdomen ct with contrast will sort out the issue if not improving.
Key . Key components to classify pain would be if there is any fever involved or not, your age, your medical history, and the results of your last colonoscopy, if any. Should you have more data, this would be a much more informative situation for you.