The pain you have described appears to be either gastritis
or gastric ulcer. That is why every time you eat something you get pain. Have you tried taking any antacids? they may help you to temporarily relieve the pain. Your doctor is right in telling you not to take any pain killers as if there is an ulcer it may worsen or even perforate.
About your gallstones, what treatment did you undergo then? Didn't they remove your gall bladder
After your blood tests come back you may need to take an endoscopy
test in which they insert a pipe in your stomach through your mouth to see the inner side of your stomach and see if there is any ulcer.
Treatment will depend on the exact problem that will be found. Till then try some antacids.