Has it occurred to you that you are a dissatisfied customer? Change doctors. . You are not a charity patient. You pay through the nose for health insurance, either directly or indirectly, and this requires that your doctor (who is doing well financially because of people like you) look after your health to the best of his ability. In this instance it means relieving you of pain. Become more aggressive.
Well, pain from surgery normally goes away after a couple weeks, depending on the procedure. But if, for example, you had spinal surgery, the SURGERY might not hurt anymore, but the spine can keep right on hurting due to those surgeries are not always successful. If the old injury or a nearby new one exists, whomever did your original procedure needs to reevaluate you. You say you have been thru tests, so assuming they do not reveal any mechanical problem related to the surgical site, this doesn't mean you won't feel pain. For example, you wrench your shoulder, it was fixed, but you have muscle spasms. They hurt a lot and yet won't necessarily show up on tests. It just hurts. If it's muscles bothering you, then physical therapy is the next logical step. Some tests to consider for mechanical problems are the MRI, which shows how your nerves are doing, and for muscle problems an EMG will see if you got spasms.
Perhaps if you would go ahead and give details of what required surgery, others on this board might can offer better ideas on what exactly is going on with you. Your only other option is to very slowly go off your existing pain drugs, if you're still getting them, and see how you do.