Hi. If this is really such pain then you need to do gastroscopy and other endoscopic procedures.
If it is associated with fever
and muscle guarding then go to ER.
Try to avoid food that triggers pain. It can also be gallbladder
disorder ,not just gastritis
. You should do US of abdomen to rule this out. There is no need to suffer. Intensive,persistant pain is a sign of something,especially if regular analgetics didnt help.
Wish you good health.