literally cant run today because my knee hurts when I bend it like 30 degrees. any advice on what to do? i think i may have overextended/overbent my knee stretching a bit too much it one day (like trying to make my heel touch my butt). I just tried going out for a run but could feel pain/tightness with each step and it was more like a shuffle no matter how hard i tried so I turned around after heading out only 0.25 miles. i think i will swim today instead. anyone get this?