There is also "Pelvic Floor Therapy" that is gaining some popularity these days. On top of having Endo, my specialist told me that 1/4 of my pain is from my pelvic muscles being so tight. (from years of having pelvic cramps your muscles stay tight and do not release after a while)
I am 40, years old and have had Endo since I was 14, my Specialist is the first one ever to tell me that I had pelvic floor dysfunction and referred me to see a Pelvic Floor Therapist.
I'm only 3 sessions into it but I was told the end results would be worth it.
If it means feeling better and taking less Naproxen, it is definitely worth a try.

Best of luck to you!

I have not had pelvic PT, but I have been in ortho PT on and off for the last year. I realize that's somewhat different, but I've spent a lot of time talking with my therapist and the staff and I hope my insight might be helpful.

When I started seeing my therapist last year, I'd had chronic shoulder pain for 7 years. I'd seen a specialist at a top hospital who couldn't identify the cause or do anything about it. My therapist almost eliminated it after 3 1/2 months. In my experience, PTs are better at working with people in pain than doctors are (they pretty much only work with people in pain, whereas with doctors it varies) and approach it differently than the doctors do. I'm not sure how pelvic PT works, but with ortho you at least start out seeing the therapist 3x/week, so they get to know you, how your body responds to things, etc. and that really makes a difference as well. My therapist also stressed to me that, while PT has a reputation for being really painful, it actually should not be. It's not always pleasant, but you should never be in extreme or prolonged pain during your treatment. It could be worth looking into, but I know it's a big decision-- good luck!