When i squat, the top of my knee cap burns. also, when i lightly touch my knee cap it feels numb. there's no discoloration?

Patellar symptoms: It sounds like you have symptoms at your patella (knee cap). Many young patients have what's called chondromalacia, which refers to worn cartilage behind the patella - this can usually be treated with simple physical therapy. It's also possible to have bursitis (swelling/inflammation) right over the patella, and patellar tendonitis is also possible. See a physician if symptoms persist.