So I was squatting a bar, finished a set of 10 ok, and decided to do a 2nd set. On the first squat I went down fast, felt my quads contract, then loosen up, with a muscle "separating" for a second, then contract back again.
It started paining, and I stopped doing any more squats. It pained for the rest of the day, but I massaged it and applied Ice to it.
Next day it was paining to walk(it feels like its jiggling more than usual), but I decided to go for a run. Felt a bit painful, but not enough that I had to change my form or limp.
A couple of my weightlifting friends think that I overstretched my muscle, or contracted it too much. I went to my schools trainer, and she thinks its either a pulled or strained Vastus medialis. She says that its ok to run on, as long as I don't do any "explosive" stuff, but I don't know if that is the case considering that she knows that this is my senior season, and she is more of a football trainer.
What is it exactly, and how long am I out for? What strengthening exercises should I start doing? Should I continue running?