Stopping pain medicine suddenly for no reason?

I have fibromyalgia, a condition that cause chronic pain through out the body for unknown reasons. I've been taking Methadone 5 mgs, twice a day plus Norco 5/325 for Breakthrough pain. I have a pain management contract for the doses noted. I have stayed loyal to this and to everything the doctor wanted. However, today when I went in and had to see a replacement for my primary care doctor, he wanted to stopped all of it, cold turkey and not give me anything for the pain I have daily. I managed to convince his boss to give me my medicine, but they both want me off of it, despite numerous previous doctors wanting to keep me on it. I live in California, and am on medi-cal and SSI for disability. Want to know who complain to, if I can sue, and what can I do to get the pain relief I need.