How tall are you?
Im 6'1, not a tall man, but above average and ive found that the "normal" shoulder width squat hurts my knees alot. I use a wide stance, almost sumo, and that takes the pressure off my knees. I also go all the way down, below parallel, as far as i can go. One of my buddies who usually goes parrallel had horrible knee/lower back/ankle problems untill he started to full squat.
I would try that first, if that doesnt work the above mentioned products are good.