To the practioners of the most noble stroke...Hip pain?

I'm a breaststroker...for anyone who confused "noble stroke" with some other lesser stroke....;) Usually the one part of my body that hurts is my shoulders and occasionaly knees, but my hip has been killing me lately. I have double jointed hips and they occasionally slip out of place, but I can usually pop them back in easily and it only takes about day. My hip has been hurting for about a week now and it's different pain then slipped out of place. Any ideas what could be causing it or how to fix it? Merci Beaucoup!