What Causes Lower Right Back Pain?

Recently I had lower right back pain that I attributed to too much golfing while wintering in FLorida-I iced it and after 3 days went to the heating pad-it seems to have helped but now the pain has mostly moved around from my back to my right side (between ribs and hip)-feels tender and tingly and wearing pants with elastic waistband -even underwear causes it to hurt. What could it be-kidney infection? Should I eat or drink something to help-had this for approx. week and half now