Knee pain is often caused by bad habits in the way we walk, stand, sit, or run. According the the National Academy of Sports Medicine, the body is a kinetic chain. When one part of the chain is weak, or moves incorrectly, the rest of the chain compensates and creates further imbalances, pain and even injuries. One such result is knee pain.
Start with the feet. Observe your feet when you walk, stand, or run. Do they point outward or inward? Is your foot rotated toward your little toe, or do you walk on your arch?
To make corrections in the feet make it a habit to stand or move with the middle toe pointed strait ahead. Try to put equal pressure on the bottom three-points of your feet; the heel, the inner and outer ball of your foot. It might feel exaggerated at first but it is important to align your feet in order to get your knees to follow.
Next observe your knees. Look strait on in a full body mirror so you can see your bare knees. Draw an imaginary vertical line from the center of your knee toward the floor. Where does this line hit the floor? If it lands toward the inside of your foot, this may mean that your knees are ad-ducted, or inward. This may be the cause of some of your knee pain. Try to open your knees until the vertical line lands on the center of your feet, where your shoe laces would be.
Next perform a squat looking strait on at the mirror. Do your knees move inward (ad-duct) or outward (abduct)? Again, try to keep them over the center of your feet.
Now perform a squat looking side-on. Do your knees move forward over your toes? Make sure to anchor your heels into the ground, be sure your aren't gripping with your toes but you can wiggle them freely. During the squat your hips should move to the rear, like you're going to sit in a chair, the upper body will tilt forward slightly. The knees should not move forward, and you should be able to see your toes as you squat.
Stretch your IT band - the outer upper-leg - and your calves. Practice single-leg balance exercises to strengthen the small stabilizing muscles in the knee.
Making correct movement is not a guarantee to cure your knee pain, but it may help, and it may even prevent an injury. It might feel strange or exaggerated at first, but over time you create good habits of moving correctly and possibly save yourself from a worse injury.