My 11 Year Old Son Is Experiencing A Lot Of

My 11 year old son is experiencing a lot of abdominal pain. Has had diarrhea and has now started vomiting just air. It is NOT a burn. this is like a violent burn. It can go on and on every minute or two for hours at a time. This is our 7th day. Saw his pediatrician on Tueday. Sent us home to use am odium and treated it like a virus that will pass. He has no fever. He had a severe intestinal blockage that sent us to the ER 3 nights in a row and then an overnight visit in the hospital 2 months ago. The blockage cleared and he returned to a normal routine. So I have no idea what is going on.
I meant to say it is NOT a Burp.