I had aches in my knee after running. But it's not the knee, it's the ligament that runs down the outside of the thigh from the hip to the shin. When the band comes near the knee, it becomes narrow, and rubbing can occur between the band and the bone. This causes inflammation and pain. ITB syndrome can result from any activity that causes the leg to turn inward repeatedly. This can include wearing worn-out shoes, running downhill or on banked surfaces, running too many track workouts in the same direction, or simply running too many miles. Unlike many overuse injuries, however, ITB pain afflicts seasoned runners almost as much as beginners.
So, the treatment is ice, a patella strap,... and NO RUNNING!
What a bummer!