It is all to common to hear individuals complaining of consistent knee pain. Medial, lateral and anterior knee pain can be the result of many things, contact and non-contact injury related. But two commonalities among 95% of the athletes and clients that I work with is the lack of mobility in the ankles and hips.
The knees are really just slaves to the ankle and hip! The main function of the ankles and hips are primarily of a mobile nature. The knees are that of a stability nature. So you can see, if the ankles and hips are stiff, the knee takes the abuse by having to a job that it was not designed for. My good friend Frank Baumholtz uses a great analogy for the lack of ankle mobility: "Not having adequate mobility in the ankles is like driving a car without shocks".....You can imagine how that would feel. That is the torture your knees are going through on every step, jump, etc..
It is amazing to see the pain literally disappear when gaining mobility in these areas!
By incorporating some ankle mobility drills (http://youtube.com/watch?v=RPa9-fpqnUE) and doing some self-soft tissue work (foam roller, tennis balls, etc....) on the hips and glutes, you will find yourself with pain free knees.
You can also compliment the soft tissue work that you do on your hips with some lunges, lateral lunges and other active/dynamic type stretches.
So....stop being a wuss and get to work!!