Knee pain,its more of a sharp pain when i bend it past and back a certain angle when i walk?

Last week thursday during pt(marine corp) we worked on lower body,the next morning i felt the knee pain when i woke up.I rested up until tuesday,i went for a light run and i couldnt.probably made it worst..anyway ive been resting since,icing it,and taking glucosamine pills.any suggestions would help i need to recover as fast as possible.i know for a fact its not a big injury as theres no pain when i dont move it and its a first time thing.thanks in advance.