Strectching, I agree, should be done after a run, practice, or some other physical exercise. However, doing said exercise can be detrimental to cold muscles. I would suggest light and complete stretching before, then sustained, heavy stretching afterward. Never stretch far enough to feel burning or tearing sensations. There should be no problem with stretching everyday. Sometimes the exercise you do before stretching shouldn´t be done everyday, for example heavy weight training. Before and after yields great results.