Have you tried a pain management clinic? Who ordered the MRI's and read them? My pain doctor sees things on MRI that other doctors don't because he does this for a living. I know this is going to sound like something out of left field but.....you may need to see a GYN. I have endometrial cancer and the severe back pain I experienced for a few years was partly from the cancer. The cancer group I'm a member of on Facebook lists severe lower back pain being a sign of possible cancer. It will not show up on routine MRI 's. I thought I had, and treated, a UTI or bladder infection. After 2 rounds of antibiotics and no relief I thought well maybe it's a female issue. I went to GYN and pap was normal. When I asked "but why is the pain so intense" he did a biopsy. I saw results on my portal before my follow-up with him and he didn't get enough tissue. Before I could get back to him I was in the ER with unbearable pain. They did a CT scan and found the cancer. So....maybe when it is actively flaring up, go to ER, crying if you have to, and let them do the MRI or CT scan there. The pain is coming from somewhere so I'd be there as long and as many times as I needed to until I got results. I hope you get relief and diagnosis soon. ❤️