HELP!!

i received a letter from the california medical board two days ago, asking me to sign a release for medical information regarding a OP i used a few years ago, and it says if i dont, it could be supoened.
HELP HELP..do i sign it? Am i in trouble?
I have used ops for several years for chronic pain, and have never used more then one at a time, but this has me a little scared.
any help, suggestions would be appreciated, i am at a loss as to whether i sign this paper or not.