How To Treat Severe Pain Caused Post Back Surgery?

hello, I am native american, from the flandreau santee sioux reservation. My age is 60 my doctor put me on pentazocine/naloxone 50 mg. I had back surgery, last feb- lots of pain still. I have heart problems and work out in the field. my job is inside and outside. please help me is this a drug like hyrodconie???