during a run about 3 weeks ago my quad started to feel pretty strange...especially on the outside bottom half (closer to the knee). at the time i chalked it up to just training making it tight, but since then it has only gotten worse. it hurts when i land and use the quad to push off. ordinarily i wouldn't be concerned except that it hasn't gone away, even after taking almost a week cross training, and i've had quite a few stress fractures. has this happened to any one else? anything help?