I recently started working with a pelvic floor PT specialists for muscle spasms down there and while I do not have the same problem you have I for sure thought my pain and burning was a cyst or something else gyn related or perhaps that bad disc in my back.

But nope the gyn felt all around in there and found the source of my recent pain and was like wow you have muscle spasms deep in your levator ani muscle and the surrounding muscles. So off to PT and I have to say it has helped my pain. not totally gone but a good reduction.

Good luck. Be sure to make sure they know how to treat pelvic floor dysfunction.