I Have Had A Pain The Middle Of My Left

I have had a pain the middle of my left buttock for at least four months now. It sometimes travels down my left leg to my ankle. I hurt when I sit in my car which has bucket seats. I really hurt when sitting on my soft sofa that is very deep. I feel the best after a night's sleep on my back with a pillow under my knees or when sitting on a hard surface such as a bleacher or wooden chair or the floor. I try to walk at least two miles a day but sometimes hurt a little during my walk. I have been taking meloxicam for the pain. sdohrmann14@att. net