I Have Been Having Low Back Pain, Hip Pain And

I have been having low back pain, hip pain and muscle cramps in my right button. I have a metal rod in my back from scoliosis surgery at 15 , I'm 46 now. It has been getting progressively worse, so even standing 10 minutes creates severe pain and pressure. I'm 5'4" and weigh 215. Otherwise relatively healthy. What type of doctor should I see? Anything I need to do to prepare?