What causes a hunger kind of pain in the middle of the upper abdomen. Sometimes eating relieves the pain & other times no. Can it be my gallstones?!

PROBABLY NOT. Epigastric pain that is relieved by eating is typical of ulcer or gastritis. Gallstones, when symptomatic, usually cause pain after eating, especially after fatty or greasy foods. Some other entities can also cause this type of pain, including pancreas issues. I recommend you seek a direct medical opinion. Good luck.
Ulcer. This could be annulcervor gastritis. You should see a professional and probably get a scope.