When i eat, what could be the cause of my stomach feeling like it is on fire? it happens with all food, not just acidic foods.

Gastritis: that is usually gastritis (inflammation of the stomach) you should try to take medication like omeprazole 20 mg twice a day for one month with mild food during this period if you don't fell better then you need more investigation it can be sever inflammation or even infection with H pylori and you need treatment watch for dark stool to make sure there is no bleeding hope you feels better