Knee stability concern - advice?

Hey all!

So I have always had a noticeable difference in my knee flexibility. For example, in the quad stretch, I have to find a good position with my left leg sometimes because it feels like I'm overstretching - in other words, a slightly pinching, not very pleasant stretching as compared to my right. Anyhow, I think I may have destabilized my knee joint and loosened it with my traininng/postures, I don't know. It kind of feels like it is just ready to lock up, you know? And certain positions like lunges seem to stretch it and hurt.

I finished FBMASS and so am taking it easier these next few days but wanted to know if any of you guys suffered this and had any conditioning/rest/remedies to help out?

I know with proper rest it'll get better, but just wondering :)