Tests done are negative but still have severe back pain, nausea, sweating CT scans, x-rays, 2 biopsies done for Crohn's & colitis. I'm 37 female?

IBD. Several types of inflammatory bowel disease also have associated spine problems. Though you've had x-rays, if there is concern for ibd, other tests, such as mri, can be helpful in looking for spine problems in patients with ibd. This would be a good topic for discussion with your personal physician.