knees

I had a question for you guys. When I am doing my squats, I notice that my knees start to hurt. I hear a clicking noise, and I also notice pain coming from them during my repetitions. do you think that I'm simply not training correctly and maybe over training? Any tips or advice?

I'm looking for the best supplement to help with my injuries my knees don't feel that good and when I workout I get a cracking noise coming from them do you think it means that my knees are too dry and need to be lubricated?

This is pretty funny but when I was using the smith machine today I felt my joints cracking in my knees I racked the weights and then went and sat down and did some stretching which supplement would work good here?