Hi. Thanks for your query. Noted the history about your son and understood the concerns. Since the age is not mentioned the following reasoning will be in general. The commonest cause for pain and vomiting especially after meals can be due to the following reasons: Gastritis along with reflux due to lax lower esophageal sphincter, although in his case the Endoscopy and barium are normal. Hence will need another investigations like CT scan of abdomen and tests of blood, urine and stool. Clinical evaluation by a General or Gastro-Surgeon or a Gastroenterologist and if needed by a Neurologist/Psychiatrist if all the investigations are within normal limits as needed or advised should help him further to pin-point the cause and get the proper management.