super tight muscles, only one side

Hi, all,

I've been working out almost every day for a little over two weeks now. I would work out every so often before, but not nearly as much as I have been. So it's not like I went from being totally sedentary to trying to run a marathon or anything. Anyway, I've been averaging about 450 calories / 45 mins. on the elliptical, 4 out of 5 days. (Usually medium resistance, medium-high incline.)

I am experiencing a super tight muscle in the back of just one leg. Just in my right leg, there's something in the back of my thigh that's super tight. It's not as low as my knees, so I don't think it's my hamstring, and it's not as high as my bum, either. The only way I've found to stretch it effectively is to cross my right ankle over my left knee and pull my leg to my chest.

It isn't a sharp pain, like when I've sprained my ankle or something like that; it just feels like it's ridiculously tight. It starts to hurt if I sit in one place for too long, like on my 30-minute drive to work. I can kind of feel it when I'm working out but it's not really painful.

Suggestions? Does this sound like something I should just stretch a lot and work through, or do I need to rest it for a few days? Should I be doing a different exercise instead for a little while? Thanks!