Before I was diagnosed, I looked up all of my symptoms online, severe stomach pain when eating being one of them, among several others. I found that the symptoms listed for celiac disease matched mine really well. I had an appointment with the doctor but before I went I did a little experiment of my own. For just a day I checked the ingredients of whatever I ate. Sure enough, I didn't get the severe stomach pains when what I was eating did not contain gluten but I did when the food did contain it. I was able to bring this information with me to my GI appointment and with it he knew right away to test me for celiac disease, which was of course positive. My stomach pain is mid-abdomen with it, which I think is more consistent with where the small intestine is located, the organ that is damaged with celiac disease.

Checking to see what ingredients in foods flare up the pain though, would be my suggestion. See if gluten does or if you can find anything else that is causing a problem instead. Celiac disease can also mimic symptoms of other conditions, so it's best to see a GI and see what he/she says, there are tests to confirm the diagnosis if it is the case. Gluten sensitivity could also be the problem.