Thank you for the query.
It is very common that gall bladder
is getting removed as a reason of pains and it turns that it was not the reason. What are you suffering from is probably peptic ulcer
(it causes pain after 1-2 hour of meal, loss of weight, but does not cause diarrhea). However some other conditions should be checked.
As you are after gall bladder removal, sometimes it happen that some small stone gets into the bile ducts and gives a lot of pain.
Upper GI endoscopy is a good idea as it will rule peptic ulcer and stomach cancer
out. But before it is advisable to have fool blood work with liver tests (AST,ALT and GGTP), pancreas tests(amylase), urine analysis and abdominal ultrasound. After this tests upper GI endoscopy should be performed and if GGTP elevated, during this test ERCP should be done as well.
If you find all this tests negative, stool tests and colonoscopy
should be performed as well. Such symptoms may be also present when partial intestines obstruction appears due to colon cancer
Hope this will help.