Also could be your gallbladder. I had very weird symptoms when I had gall bladder disease.
it can be a simple ulcer since it gets better with food
do u have G.I. problems; gas, bloating, diarrhea, constipation, flatulence etc
NEXT time before eating try this; teaspoon of baking soda (bicarb of soda like Arm and Hammer in yellow box in every cupboard) in 6 ounces tepid water
how ever it could be gas, pancreas, liver, on and on as it is a common complaint
good luck
it might be your kidneys.. try to drink lots of water or cranberry juice i had that happen to me before it hurts so try and do that and if it dosent improve in like a week or two call your doctor up.. good luck.....