Knee pain in petella tendon area. hurts when sitting down too long or standing up. ?

Torn miniscus, bursa: The more common causes of your symptoms are petallar bursitis (the patellar bursa becomes swollen, irritated and painful), and a meniscal tear (tearing of the cartilage disc between the femur and the tib/fib complex. If it persists for more than a few days, you need to see an orthopedist for an eval and knee MRI. In the meantime, an adjustable brace would not hurt, and would give support.