Hello, I work in neurophysiology and spine surgery. It sounds from your MRI that your back pain may not be nerve related. If your doctors did not find any stenosis, foraminal narrowing, or disc herniations, then I would trust them on that. You may have a painful muscle spasm or something else going on. Most patients that we see will not need surgery if they keep their core strong to protect their spine. I would continue with physical therapy, and possible look into some type of posture correction while sitting. I assume you sit for 8 hours a day at your job? Maybe look into buying a standing desk, this will help you maintain core strength, as it is very hard to do sitting for 8 hrs per day. Good luck.