I think Alina gets it right. As long as the pain isn't too severe she can continue to be active and once she's fully grown the pain should stop anyway. She's grown a lot lately, that'll certainly make her condition worse at the moment.
I don't think so. Eteri's statement is correct, as far as I know. If you have it, you have to endure it. The pain should go away eventually.
I had something similar to Osgood–Schlatter as kid and teen (never diagnosticated properly, and i just outgrew it later). It is uncomfortable, but then you kind of get used to it. It would hurt regardless, you can stay at home or go run around, so at least you have fun.
Also, stretching and proper exercises (which Alina surely gets) help to reduce the pains long term, rather than make it worse.

