Over the past year or so I have been experiencing knee pain when at work. I am a server so I am constantly on my feet. I wouldn't describe it as debilitating but it does feel like it is getting worse. Sometimes it is in the front of the knee but lately it has been in the back of my knee and kinda getting down into my calf. Sometimes my right knee hurts, sometimes it's my left, sometimes both, it seems pretty random. I have been on the Primal Diet for a while now and everything I read online says that knee pain is typically caused by obesity, elderly age, poor diet and a sedentary lifestyle, none of which apply to me. I am 26 years old, I am 5 '7 and I weigh 120 pounds and I stay pretty active. I recently started lifting weights and eating more because I am sick of being scrawny, doesn't seem to have much of an impact on the knee pain one way or another. I do have pretty extreme flat feet, I'm thinking that might have something to do with it. Any ideas?