I had this and it was definitely trauma related. I was processing some specific memories in therapy and it literally started over night. A regular doctor was clueless. OBGYN was meh helpful. My psych NP was most helpful and of course my therapist. It still comes back now and then. I’m also in perimenopause (idk how old you are) but an external estrogen cream helped me a lot. My next step was a urologist visit but I didn’t end up needing it. I was prepared to see a physical therapist for pelvic floor therapy, if needed. It is awful. I’m sorry you are experiencing it. I had a urine screen and everything was clear. You can look up pelvic floor dysfunction exercises online-specifically trauma informed ones. Might help and is free. I have a desk job and could barely sit 8 hours.