Is a doctor allowed to do this?

I went to see a doctor, I don't have insurance , so the appointment cost 295$ I went and talked to the doctor about my back, and showed her my MRI and Xray and she prescribed me 10mg of hydrocodine 3x a day. With a refill for the next month, after 2 months the prescription ran out, I called to have it refilled and the doctor said I need to come see her again (for another 295$) I can't afford to pay 295$ again and now I am in a lot of pain and nauseous and shaky from taking the medicine everyday then all of a sudden stopping. Is that fair? Or allowed to do for chronic pain sufferer ( I have scoliosis, 3 slipped disks, a herniated disk, and degenerative disk disease) the only other option is surgery which is told by my doctor to be risky with 50/50 chance of being worse than before after the surgery. not that I even had the insurance to pay for that even if I wanted to chance it.