Just adding to flaps forty:
Get checked out by a doctor for alergies and probably go see a dietician if you think it could be food. People find out that they may have certain allergies that cause these pains and a change in diet may be all that it takes to get rid of them. EG Celiac (or Coeliac) disease which is due to a reaction caused by gluten in the diet.
Thats just one example of the sorts of things that have been discovered by medicine in recent times.
Take care of your health before you start flying.