I am sure you know where the pain is...but I have to ask. Are you sure it is your stomach. A lot of people feel pain in their gut and say "Ow, my stomach hurts" You stomach is actually on your left side slightly above your navel. if it is under or around your navel it is the intestines.
I am sure, as most of us are here, that you know your anatomy as we all have learned it from this disease but I wouldn't be me if I didn't ask. Now..if it is your stomach..has your GI looked at the possiblity that the CD might be there also. Don't forget that CD can go from your mouth all the way to your anus.
I hope you feel better and before someone else suggests it..have you tried liquid supplements instead of regular food?