My 16 year old son has nausea and vomiting. It happens about every three weeks. He was hospitalized in March and they ran every test, endoscopy, colonoscopy, ultrasounds and say nothing is wrong. Today when we went we went out to lunch, he said his stomach felt weird and he did not eat much. He ended up throwing up a lot on the ride home. He ate the same things that he eats at home and has no problem. Three weeks ago he had the same problem, but was not riding in a car, was at home. What doctor do you suggest we go to next? We have been going to a pediatric G.I. I am very worried. Thanks!