Suggest Treatment For Painful Hip Bursitis

I am 62 yrs young, 5ft 4 inches tall & weigh approx. 240 I have very painful Bursitis in my hip. What causes bursitis? It feels like where the hip bone meets the leg bone down deep inside there is a sharp constant pain. I cannot sit on anything hard, I usually sit on a pillow, it hurst when I walk & go up stairs. The pain goes half way down the back of my leg to my knee. In August it will be 2 years. I have been to therapy and had & had something called needeling, & laser therapy, It helped the very 1st time but noit after that. I have had massage therapy & that made it hurt worse. I have seen a rhuemotologist & she said I do not have RA. I went to the chiropractor and he is the one who told me it was bursitis. Then I went to the Dr. & had it xrayed, he said he did not see anything on the xrays. It was so bad I could barely walk. The Dr. gave me a cortisone shot and I was already on anti-inflamatories. The shots only last about 3 to 4 months and I have had 2 of them and now it is hurting pretty bad so it is time for another shot. The shots do not make the pain go completely away but at least it is bareable. This just came on al of a sudden. I did not injure my hip. The cortisone shot is a steroid so that causes weight gain, sleeplessness and messess with my blood sugars although I am not diabetic that I know of. I hope you can help me.