On & off fever, terrible nausea, loss of appetite and burning in stomach and under right rib cage into back. can't eat without pain only want fluids. ?

Gall bladder issue: If you are having a fever with significant abdominal pain you need to be seen by a physician. This could be a gall bladder problem that can become quite serious. The gall bladder is in the right upper quadrant of your abdomen. If it gets inflamed or infected you can experience pain in the right side, mid abdomen, right shoulder, and between the shoulder blades.

Infection: it sounds like an infection but I'm unable to give you a definitive diagnosis I would suggest that you see your physician have a complete examination and required blood tests