What could feel like kidney infection but isnt? dull, burning like pain in left back side under ribs and above butt. urine was positive but culture was negative for uti. been going on two weeks. normal ct of pelvis/abs and norm vaginal ultrasound?

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It may be musculoskeletal pain. Try regular aerobic exercise. Raising core body temperature through exercise will improve strength and flexibility of muscles. Drink enough water so your urine is mostly colorless. Wish you good health!

There are too many organs and structures in those areas to make a judgment. If in-person care from your own doctor hasn't given an answer, a distant forum doctor certainly cannot do so with such limited information. If you're not confident in your doctor's evaluation and plans, feel free to seek a second opinion, e.g. from an infectious diseases specialist or urologist. Good luck.

I agree with the mentioned advice. Another possible cause of your discomfort could be a nerve pain as a spur or bulging intervertebral disc pressing on a nerve root in the midspine. An MRI would be able to detect such a problem. Discuss this with your MD if no other diagnosis can be definitively made and your discomfort persists.