Symptoms of Patellofemoral Pain Syndrome
The most common symptom of patellofemoral pain syndrome is a dull, aching pain in the front of the knee. This pain-which usually begins gradually and is frequently activity-related-may be present in one or both knees. Other common symptoms include:

Pain during exercise and activities that repeatedly bend the knee, such as climbing stairs, running, jumping, or squatting.

Pain after sitting for a long period of time with your knees bent, such as one does in a movie theater or when riding on an airplane.

Pain related to a change in activity level or intensity, playing surface, or equipment.

Popping or crackling sounds in your knee when climbing stairs or when standing up after prolonged sitting.