@dfo this isn’t something that is easy to talk about with most people so people suffering from such are mostly alone. I’ve experienced it as well unfortunately. With varying results of different things that I have tried.
most likely comes from a tight pelvic floor, and there are physical therapists who can help with this in fact that this is their specialty. If you could tolerate someone getting intimate with that part of your anatomy, which I am not. there are certainly exercises you can practice to help you relax that area, which may help also many of which are online meditation techniques, hypnotherapy techniques, etc. make sure you’re going to a competent, qualified and certified person of course.