Your doctor can alter treatment in any legal way that he or she believes in medically necessary. It sounds like this guilty plea has led your doctor to believe that you were simply faking the injury/pain in order to get the pain pills. Hence, he took you off the meds and canceled the specialist referral. You may go to another doctor, but I'm not sure you have much legal recourse.
I am in no way giving you legal advice. This answer does not create an attorney-client relationship or otherwise imply that I have intended to form such a relationship. You should sit down and discuss your case in detail with a trained and licensed attorney in order to determine your best course of action.
Doctors cannot be forced to treat people. Time for you to find a new treating doctor.
DISCLAIMER: David J. McCormick is licensed to practice law in the State of Wisconsin and this answer is being provided for informational purposes only because the laws of your jurisdiction may differ. This answer based on general legal principles and is not intended for the purpose of providing specific legal advice or opinions. Under no circumstances does this answer constitute the establishment of an attorney-client relationship.