Tweetuse a foam roller and roll out your glutes, hams quads etc. many of times it is cause by a tight a small muscle called the piriformis or tight low back and other muscles. the pain down the leg is referred pain.. You are probably loaded with trigger points. Roll, hydrate, lay off the motion of bringing the knee up like when you do stairs or elliptical, for a while till it feels better. Also don't sir for long amounts at a time when it is flared up