why would my pain management Dr. give me a narcotic pain shot to alieviate the excruciating pain in

I am 45 years old. granted disability in 2001. Have been a chroniic pain patient on narcotic agalgesics for the last 10 years. I currenty receive 40mg-am   20mg-noon  and 40mg-pm, which still doesn't give me any better quality of life, as I researched and found out that was what pain mangement was all about. When I saw the Social Security Dr. that approved my disability he notated that my pain was not well controlled at 40mg twice a day. I have been through living hell for the last 10 years of my life and have at some point and times thought of just putting myself out of misery because the Dr.'s just didn't get the concept that my body is so tolerant to the analgesics that they are just not doing my much to tolerable unless I take more than prescribed. I have time and time again tried to explain this to them. They just act as though I am a drug seeker....I have have had to recent surgeries....osteotomy...I believe it's called, where the spine doctor whet in and cut out wedges in my spine in two different locations, so he could straighten out my back....I was bent over like an 80 year old man....That went terrifiec.....I had my left hip totally replaced in March of this year, and am scheduled for my right one to be done on the 11 of Sept. The thing I don't understand, is why they wouldn't give my a shot for relief in my right hip when it is killing me....I understood why they wouldn't do the steroid injections, so I could get into surgery asap....but I am just so miserable and in intolerable pain all the time that life just doesn't feel like life at all....it just in-humane torture to me. When I have begged and pleaded and tried to explain to the best of my ability....When I did get some steroid injections last year the doctor said I had the worst hips he had ever scene in his career....So it's got to be evident that I am at an elevated amount of pain. Why are they so reluctant to treat me with stronger medications...I am not suicidal.  Just want some damn relief and quality of life...not just to woller in bed and moan and groan all the time.  Hope you can help me understand. I have had many MD Dr.s give me pain shots...whey would they refuse me when I am extreme acute and down right awareable pain?  Should I locate a new pain management clinic? If so I sure would like a good referral down here in Southeastern NC on border of Myrtle Beach SC.....Right now I am keeping all my medical needs at Atlantic Orthodpedics.