Since UR approved the treatment, you should not have to pay for anything. If there is a billing dispute that is between the medical provider and the defendant. Go get your treatment and get well soon.
Mr. Epperly is correct that since UR approved, you won't have to pay anything for pain management.
Ms. Harris is correct that now you need to find a pain mgmnt program willing to accept fee schedule.
Mr. Epperly is correct that you also need to find a good WC attorney. Yoshida & Nelson are both very good. David Rockwell is one of the best in California. Find all of them here at www.avvo.com or at www.caaa.org.