Hi. Thanks for your query and an elucidate history. The most probable cause of pain in the absence of any finding for reflux, wheat allergy and Lactose intolerance are: There can an inflammatory process going on in the abdomen as appendicitis or diverticulitis or lymph node problems. Or there can be narrowing in the upper part of the intestines. I would suggest you the following for your daughter: CT scan of the abdomen Enteroclysis , a sort of Barium studies. I am sure the reason will be found, get investigated and treated accordingly.