My hips do not get sore after sex, but sometimes during my period they get a little tender. For me it just feels like a continuation of cramping. It almost feels like the cramping in my abdomen area extends into my hips and even my upper legs. I do not know if stretching will help. I am very athletic, and I do not get any relief from stretching or exercising. I just take some Tylenol, and wait for it to pass.