Tummy cramps, diarrhea up to 4 times a day. stomach currently burning like fire inside. blood tests all normal. stool tests all normal. scopes all normal. what next?

If everything is: normal but symptoms persist, it may be a food allergy or psychological problem. See an allergist first to rule that out and then consider counseling.

Food allergy?: First I would eliminate dairy to see if this helps. I also presume that you have had a negative celiac disease test and no parasite in the stool. If these symptoms occur within 2 hrs after eating, I would suspect food allergy or intolerance. In which case, an allergy consult may be in order since you have already have a GI workup.