C.M.
After my first baby was born, I had to have my gall bladder removed. Since then, I have not been able to eat Chef Boyardee products either. Same problem as your son. I believe (this is not confirmed by a doctor by the way) that it is because of the high fat content in these products. Boxed macaroni and cheese does it to me too but not as bad. If he loves the ravioli, try getting the freezer kind and Prego or whatever sauce you like. It is much healthier for you. It is more expensive but worth it if it solves the problem.
You should be able to find a nutritionist through your insurance or you could have your pediatrician refer you to one as well.