Hiya, I recently did the Bristol Half marathon and my hips (my hip flexor muscles right at the front?) not at the joint I don't think...more muscle soreness were killing me after it. My dad got me into running when I was younger and still runs now, and he asked me "does it hurt more in the right than the left?" Yes I answered. I'm approaching 30, and he told me that it must be a family genetic thing, but from reading this it looks like quite a common runner injury...and why the right hip? I do know that there is something to do with the Q angle of the pelvis, and women have a wider Q angle, which means it's harder physiologically for women to run long distances. Well that's the sciencey bit I know. Maybe someone should reserch into it, but I definitely would say stretches would help out, if you have shortened certain muscles, due to running.
My hips were fine after a few days when i put ice on them both (especially the right one), and rested. I was able to run 2 miles 3 days after the half marathon...by the way how long should you rest after an event like that?