I had SHARP knee pains when doing heavy leg extensions, I dropped them and then dropped the pain. still doing descently heavy squats and loading the hip sled.
Occaisionally I get a phantom pain of the same sort when i get out of form in a squat
because my back is fatigued and the weight shifts to my toes.
oh and as far as the getting cut, the buddy that inspired me to start lifting tore his ACL and had arthroscopic surgery. he was squatting 85% in less than 3 weeks.
I doubt that is your problem, I had a case of bursitus because of my hams were way to tight and it actually re-aligned my foot so i was putting undue pressure on one side of my inner knee, inflaming the outer bursa pad.
so the therapist gave me some streches and exercises to do ,it was fixed in 2 weeks.
there are people out there that understand joint mechanics way better than ordinary people, that is what they do. if your knee is damaged find out if it is. It wont "just go away especially with th epoundages your doing in your squats, "(475 x 10)"
oh and i would drop the leg ext.
i hope everything works out for you.