PLZ help......bone disease/cheer injury?

[AZ All Star Cheerleader]

Latley during cheer, my knees and ankles have been hurting very much when I jump, stunt, walk or even put any pressure on them. I don't remember their being one incident, they just started hurting when i started cheer. They feel like there is so much pressure on them, like they are going to crack any second. There are no sighns you can see from the ouside except they are a bit puffy on the bottom. I talked to my doctor, and she said i might have (this is a big word so i'm going to try and spell it, then sound it out) aushkerslaughters disease (aush.ker.slaut.ers) something about hom my muscles aren't catching up with my skeleton....does anyone know how to help the pain or any information about the disease or anythng esle it could be? (I have already tried like 20 knee braces, didn't help...) thanks in advance!
if this help i am 13, 4'10 and 82.5 lbs.