I have been dealing with this in my left glute. I took a baseball to it and worked it into the muscle area. It eventually loosend up and went away.
it's my left glute too.... i really got into yesterday with the foam roller and did some good stretching. helped a ton and was pretty much gone this morning getting out of bed. the pain when it's bad is unreal!!... and even I can't believe it just goes away after walking around for a while.