Could this be a soy allergy?

[Missy F]

I have been having abdominal pain that spreads to the back and sides for about three months. I been to lots of doctors and had tons of tests and they are not sure what is wrong. I know that two of my worst attacks came after eating at an asian restaurant, which makes me think it is related to something like soy. Everything I read about soy allergies doesn't seem to match these symptoms (abdominal pain, side pain, back pain in my flanks and between my shoulder blades only.) I do not have nausea or diarrhea or swelling or hives. I get intense attacks after eating at the restaurant, but the rest of the time it is a constant mild pain. I know I eat plenty of soy in everything. Anybody else with soy allergy have just those symptoms?
I usually have sushi, miso soup with tofu, and teriyaki salmon. I do not normally eat MSG on an everyday basis like I do soy, but then I guess MSG could be hidden in everything like soy is too.