Tennis injury help?

ok i play tennis a lot
training to be proffessional.
the problem is that my knees hurt bad.
like when i bend them i have a pain like under my knee.
because of this i cant do longes
i went to the doctor to get my feet check because i have uneaven legs one is like 1mm shorter
they said that that is nothing and that they gave me these things to put in my shoes then if it dosen' t help then they will cut a part of a bone out of my heel
back to the knee
at first it is kinda hard to run but then when it warms up i am ok
by the way i am 11

Well,I have this theory that SHOES REALLY JUST SUCK these DAYS! What kind of shoes specifically are you wearing and how old or new are they?? I have yet to find any quality sneakers from specialty stores to the common shopped shops in malls, online they all seem to be hard and without any REAL SHOCK ABSORBENCY.When I went into Boot camp I purchased some new running shoes(NIKE) and then bought a second pair soon after and the story continues from there with Reeboks to K-Swiss,Adidas,all the brands and even newer ones THEY ALL are WITHOUT!I have had the same REALITY with ALL little kid shoes.So,my family and I suffer from no shock absorbency and well what is the solution...I have yet to figure that out.I have tried to find shoes from the 80's and 90's,NO LUCK!They have cheapened all the shoes located here where we live in Columbus,Oh.Maybe this hasn't changed where you live...All I can suggest for a test per any shoe is to Remove the INSERT,how thick or thin is it? While thats removed,put your fingers in the toebox and press w/your fingertips then do this again in your Heel rest area, How does this feel to your fingers,pleez be Honest?SHOES are for PROTECTION but more and more they are just fashion, they are the EYECANDY that seals the SALE hands down!! My girls think that the shoes feel fine,just fine ISN'T good Enough! but teens find this difficult to see as well as ALL PPL of ALL AGES! Best wishes to you.Sorry I haven't any solutions but hopefully, just maybe, you found the cause.

You're eleven, so there's a good chance they're just growing pains. Your bones are stretching and you feel pain as that happens. But of course your doctor knows best and knows you, so you might want to pose the question to the doctor.

Stretch more than you usually do before you play tennis. That might help to warm you up and get you going so you can play tennis more easily.