I know you said you dont have any inflamation, but have you been checked for crohns disease? your symptoms sound just like mine, and i was diagnosed 6 months ago, if you have this condition typical "good foods" for you are really bad, like the fiber, your not supposed to have any fiber, no nuts or seeds, no raw fruit especially stuff like lettuce. no whole grain.
before i was diagnosis i was getting what i called "attacks" every other month, i was missing work like crazy!!! and Im not one to miss work. since ive been diagnosied i havent had a single attack since, i guess it due to eating blan foods.
i could be wrong but just wanted to throw you a possibiilty.
Lisa