Knee pain from double pedals

So i drum every day, and i get knee pain from using double pedals. I play quite fast. So the pain isn't on when im actually playing, it comes when i extend my legs after playing. Recently i took a 2 day break, didn't have any knee pain because of it, then i started drumming again and it started. What could it be? Am i playing too tight or something like that?

Knee pain from double pedals