you could be experiencing ligermant looseness somewhere in the body if you can rember any injuries? that would explain why the muscle spasms wont go.
use yoga and physical therapy if that does not cure the spasms its more than likely a unstable ligament in the pelvis causing the muscle to tighten to stable the ligament this will cause you to loose controll of your pelvic muscles and make them spasm speak to a qualified prolotherapist. if this is the case tighten the ligament and your symptoms will be gone.
You would most likely benefit from seeing a Pelvic Pain Physical therapist. Just relax sounds great however that is like telling someone with a muscle spams in their leg they need to just relax....,
There is a book called Heal Pelvic Pain by Amy Stein that is really good, however
I would encourage you to use it along with going to a pelvic pain PT, not instead of!
I went to one after years of treatment, and she was excellent. She showed me that my pelvic floor was in a constant state of spasms! They treat both men and women!
Shelly
Learn to relax. I have to force myself to relax, don't even realize I am tense until I think about it. After years of treatment and tests I can make myself feel better by just consciously relaxing muscles in that area.