Hi. Thanks for your query. Noted the history and understood the concerns. Throwing up and sever pain above the belly button is the major complaint of your boyfriend. Since this is of long-standing nature and has made him pale and has sometimes diarrhea the probable cause s can be as follows. Gastroenteritis of chronic nature. Irritable bowel syndrome also called as IBS. Ulcer and other things you mentioned. Tests of stool for three consecutive days. Tests of blood particularly for CBC, thyroid, liver and kidney functions, thyroid problems. CT scan of the abdomen. Upper GI Endoscopy and colonoscopy. Clinical evaluation, examination by a Doctor. All these things will lead to a proper diagnosis and give a plan for proper management. The treatment has to be done strictly after proper evaluation and getting the correct diagnosis to be most effective.