Infant With Chronic Abdominal Pain Since Birth And Acute Gastritis Suffer From Pain While Urination. Need Suggestions

My 16 month old has had chronic abdominal pain since he was born. At 4 weeks, he was hospitalized for acute gastritis . Basically his bowels shut down was what I was told. He has had a series of tests-- upper GI, barium enema, ultrasound , X-rays--all showed he was full of gas but anatomy was fine. This was at 4 weeks. At 8 months he had an upper endoscopy that showed gastritis again via tissue samples. PhProbe also confirmed reflux . Since that time, he has suffered acute pain each and every night in which he cannot pass any gas. More recently I ve noticed that at night, his diaper is dry for hours (8) and he screams in pain until he finally is able to urinate and then he falls asleep. He doesn t have a fever . He is exclusively breastfed (no cows milk as he reacts to it); his diet is very high fiber . And he has bowel movements every 1-2 days that are soft. We are followed by GI and are scheduled to go to Cleveland clinic in a few weeks but I m trying to see if anyone of you might have an idea about this horrible puzzling problem. Thank you.