LunaticSoul, it can be caused by tension and fear, which can make all the muscles rigid. People often get severe back pain or headaches from stress, and it's caused by the muscles going rigid.

As you're researching and looking for another gyno, ( a good suggestion) it might help you to practice all over body relaxation. Relaxation exercises can be found all over the internet. I've even seen exercises for learning to relax the entire pelvic area, including the vagina.

Enjoying sex is very hard if our bodies are all tensed up. It may take several months of regular practice before you even begin to get good at relaxing your pelvic muscles. After a while, you might try masturbating with something small, like the size of your thumb, inside you. Over time, you can increase the size of the object -- very slowly so you don't experience pain -- while self-pleasuring. It's one of the ways pelvic muscles spasms can be treated.

You can do that on your own while you're searching for a doctor who is willing to offer you practical help so you can enjoy sex, but when you're ready for that. I wish you the best.