What Causes Painful Sores On Thighs And Buttocks?

I have very bad sores on my thighs and buttocks. They are very painful. I have had this problem a long time, around 30 years. Usually though it is on my arms or legs, this time it is on the outer thighs and buttocks. They itch, burn and hurt alot. I was put in the hospital last year and was given very strong anti biotics but the sores are still there. Maybe not as many but just as painful. I can hardly sit, it is hard to work as I sit at a computer all day. Is there anything I can do other than all the meds. They made me sick all the time. Help!