I am a regular runner. last week during one of my runs, my hip went numb and I couldn't feel my foot. once i got home i was fine. on friday, i was sitting outside with a friend for lunch. after an hour, i stood up, and couldnt straighten my leg without causing severe pain behind my right knee. sometimes when i stand up, it's fine, but other times when i try and stand, i cant straighten my knee and i get shooting pains behind my knee.