The weirdness could be instability in the joint. If it's not sore work the hamstrings for strength. Do this and you increase the strength of your cruciate ligaments inside the knee. Most athletes don't train their hammies enough and their knees are the first thing to suffer. Mega slow (especially on the way down) standing hamstrings curls with knees together might help to start with. 3 sets of 10 twice a day slow as you can.