Unfortunately because of abuse in this area, not just by the patients who have been prescribed these drugs but by the doctors and pharmacists who over the years have too readily supplied them, there is very strict accountability. A physician is simply not allowed to prescribe more than a certain amount of controlled substances per month for any one patient, and he is required to log who gets such drugs and in what amounts into a state and Federal data base.
In short, he can indeed go to jail and risk his license to practice medicine by continuing to keep you on opiods in an amount no longer allowed under state and Federal law. His fear is not unfounded, and even though you don't have a history of abusing the prescription, he can refuse to prescribe that medication further and to refer you to a pain management clinic for further care.
Further, the law cannot force a physician to order a particular course of treatment, even if it's legal for him to do so. He is free to use his own discretion, just as you are always free to look for a physician who would be willing to provide you with what you seek.
It is true and unfortunate that this does cause difficulties for many patients who are not drug seeking in an illicit sense but who need these medications in a higher amount than allowed by law in order to cope with their pain issues. All you can do -- apart from lobbying to force legislation to change the law -- would be to continue to work with this or some other pain management center until they finally get you something that will give you the same level of relief that you formerly had.
I am very sorry to be the bearer of bad news.
I know that this is not the answer which you want to hear. But it is the only answer that I can give you. The law does not account for the kind of exception that you and patients like you would require. You may want to discuss your condition and effective treatment options with the medical experts on this site.