Most GI illnesses don't cause pain in one's arm, and so I would suggest that your doctors make sure that this pain you are experiencing is not related to any potential heart disease. Beyond this suggestion, there are many potential causes of upper abdominal pain, including acid reflux (which almost always improves on acid-reducting medications), Helicobacter pylroi infection (which requires both acid-reducing medications and antibiotics), bile (alkaline) reflux gastritis (which does not respond to acid-reducing medications), hiatal hernias, gallstones, biliary dyskinesia (abnormal function of the galbladder and bile duct sphincter muscle), chronic pancreatitis, kidney stones, and irritable bowel syndrome, among others.
Since I am not involved in your care, I'm afraid that I really cannot speculate as to what, precisely, is causing your symptoms. I hope that you can find a good Gastroenterologist who can try and help to sort things out for you.
Sincerely,
Robert A. Wascher, MD, FACS
www.doctorwascher.com
Author, "A Cancer Prevention Guide for the Human Race" (2010)