I agree with matrix, GI issues make up the bulk of the problems along with stress.
Look into food first. Eliminate processed foods, sugars, fillers, fruit juices and alcohol. It prob wont hurt to go on a low carb diet for a while. Keep it at meat, vegetables, nuts and fats. From my experience, I noticed that carbohydrates need a lof of digestive enzymes whereas fats and protein dont really need a whole lot.
If that doesnt help then look into the other factors I mentioned like thyroid, and liver function as a whole.