My 7 year old son with stomach cramps

  I took my son to the dr. yesterday because he has been complaining of stomach cramps for almost 2 weeks straight.  He is fine most of the time but then will come in crying because his stomach feels like he is going to throw up.  No other symptoms such as vomiting, diarrhea, constipation, heartburn, etc.  Just stomach cramps that will sometimes last an hour and sometimes 10 minutes.  The dr. did a blood test for bacteria which was negative.  He went in for an upper GI this morning and the dr. said he looked fine, but would further study the films and let my dr. know.  
  He has had this off and on since he was 3 or 4, but recently started complaining daily.  We tried stopping milk products with no success.  He has just come home from school complaining again.  Help!!!  Any suggestions on what to do would be greatly appreciated.
Dear Angie,
Unfortunately the Gastroenterology and Liver Diseases Forum no longer has the availability of a pediatric gastroenterologist. You may want to post your message in the Maternal Child Forum.