What would this knee pain be?

Ok, I used to have tendonitis in my ankles, and I don't know if it can spread to your knees, but most of the time when I play bball or run my knees just feel fragile like something could happen any second but then sometimes they just play HURT right underneath my knee caps. Does anyone know what this pain might be? Did the tendonitis spread to my knees? By the way i'm a 14 year old girl lol