Tight hip on one side

I've been experiencing tightness on the outside of my right hip for a couple weeks (the muscle pulled in a figure-four stretch if that helps clarify). I'm pretty good about stretching consistently and it hasn't improved or changed so i'm beginning to think it's not just a tight muscle. It doesn't bother me when i'm running or walking just notice it when stretching. Should I be worried? Any tips? Want to stay ahead of it as i'm increasing mileage in training.