Hi welcome to Health care magic forum.
Thanks for asking a question to H.C.M.Forum.
You are getting stomach pain, and to the back, it comes and goes,
vomiting sensation, but no vomiting. Gastroscopy, U.S.G.,
colonoscopy, appetite and bowel movements are normal.
It appears to be functional, as there is a history of cancer you might be feeling the pain. Besides i advise you to follow some recommendations.
Avoid taking more of spices, junk foods, and oily foods.
Practice
yoga,
meditation, reading books of your interest, and hearing music. Try to mingle with people as much as possible.
Wishing for a quick and complete recovery.
Best regards.