For the past week , 20 minutes after i eat i have diarrhea my gall bladder was removed march 1994... the stomach pain is underneath my belly button.

Change diet: You may have one of several problems, and my first suspicion is a food intolerance of some sort. First, add a fiber supplement like metamucil and cut out refined sugar and hfcs. Don't drink when you eat. Try removing food items one at a time, like wheat, dairy, or tomatoes. If the removal doesn't fix the problem, add that item back and try something else.