I have burning that started in my lower back, and moved up higher to mid back which is constant. anxiety and nausea as well. urinalysis was negative.

Burning c/w spinal: Spinal nerves when irritated by swollen facet joints, bulging discs, poor posture, or foraminal size reduction (the holes in the sides of the spine from where spinal nerves exit). Also disc narrowing can also pinch on spinal nerves causing the kind of symptoms you have. Anxiety often accompanies pain of any type. See your pcp for lumbar imaging to determine the cause.