I am not trying to be a doctor, i am just suggesting a possibillity.
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I'm pretty sure it's osgood schlatter's syndrome, yet i dont know anything for sure so dont bank on anything i say. That is what i have, and in the minor stages, it hurts slightly when you're doing physical activty right? well the basic science behind osgood schlatter's is that when you hit a sudden growth spurt, then your bones may grow faster then your tendons, so it puts extra tention on your patella tendon, making it pul away at your upper shin, making that whle reigon hurt. take a look at your knee and if there is a small bump in the bone below the knee cap about an inch, it could quite possibly be osgood schlatters. I have visited many doctors about this, and they all say if you wrap something tight around the lower part of your knee, to keep the patella tendon in place (like a guitar fret is how i picture it) then you should be fine with all athletics. But sadly, i have wrapped mine up good and tight even with the bands specially made for this, and it has beeen getting worse and now i am close to getting off of my legs completely. so BE CAREFUL.
It could never hurt to put a patella band on the effected knee(s) and take some ibuprofien though. Just be careful and let pain be your guide
Remember, i am no profesional, just a teen who is also 5'10" who has a story similar to yours yet further along. so i can very easilly be wrong.
PS. the doctors also tell you to ice it then heat it after to help with healing. it's what i do every day for a half hour or more.