Chronic pain in the front and center of the knee (anterior knee pain) is common among active, healthy young people, especially girls.
It is usually not caused by any particular abnormality in the knee and does not mean that the knee will be damaged by continuing to do activities.
Pain located in the upper shinbone area below the kneecap is a different problem, and information about this can be found atOsgood-Schlatter Disease (Knee Pain)