You need to do a minimalist diet.... no gluten... no fat... no dairy... no spice... fruits and veggies are hard to digest so stay away until you can figure out which ones you can eat.
Eliminate everything for a couple weeks. Keep meals bland and plain steamed white rice and unseasoned grilled chicken is a good dinner. Then pick something and add it back in slowly. White rice with chicken and add peas for a week if your still fine try a different veggie and put peas on the OK to eat list. If it gets bad put peas on the not OK list go back to chicken and rice for a week and start with a new veggie then.
For me white rice, unseasoned shredded pork, diced avacado, and low fat shredded cheese. YUMMMM