Plyometrics makes me cringe, its really brought out the worst pain in me. The knee pain you are describing sounds like IT band to me, becuase it sounds like its more of an overuse issue, than like an incident like a blow to the knee. Where is your pain located? Your IT band inserts at the bottom of your knee to your hip. Rest, massage and ice massage pretty much cured that and lots of stretching, but for me it did take time, but it sounds like you caught it somewhat early so hopefully it will be easier to fix
Laura