What Causes Severe Pain In The Buttocks?

I had my left hip replaced about 4 1/2 years ago. For at least the last couple years its hurt me deep in the cheek of my buttock. I ve talked to the doctor several times about this so she finally prescribed me Cymbalta as a pain management medication. it seemed to help for awhile but its failed me for a year now. I take Tylenol and ibuprofen on a daily basis to help with the dull pain I have. By the end of a day its nothing but a nagging dull dull pain deep down in my cheek. I haven t went to an orthopedic doctor for a couple years, as the one that did my surgery had left the hospital. It stresses me out everyday and I often wonder why I even went through the surgery, only to have pain again, just in a different place. they ve told me before that that s where I would feel the pain from the implant. Why does this hurt so bad and what should I do? Mary Crites