I would warm up with walking or bike and work on light stretching. It's knotted up and you have to loosen it back up slowly. Try hot tub if you have one, then easy stretches and some massaging. Nothing forceful, just till you feel the slight stretch until you get your flexibility back. If you can do squats and it doesn't hurt, then I say go for it, just don't go crazy. BTW, what did you do to pull it?