Low and to the sides is the kidneys. To alleviate kidney pain and help draw out toxins grate up some ginger and boil it in a big pot and let it cool to the point that it's pretty hot but you can stand to just touch it. Soak a towel in the mixture. Lay on your belly and put the hot towel folded to a size the will just cover the kidney and put a piece of plastic over the towel and another dry towel over that to help retain the heat.