I only consulted "Doctor Google" about this and I'm pretty sure it's the so called "ITBS" or a problem with inflammation of the Iliotibial Band...most likely caused by my poor running form.
In my experience, knee pain was the result of using shoes that didn't match my stride (or were worn out).
By wrong shoes I mean, have someone analyze if you are a pronaotor, supinator, or neutral runner and buy shoes accordingly.
I used to get knee pain when I didn't toss out my old shoes when they were worn down and replace them. But once I replaced my shoes (and stopped running for a few days to let the pain go away), I was fine.
That's the best I've got.