My knees hurt, and I'm only fifteen.?

it could be arthritus or that your not excercising or in any sport

When we grow our whole body grows so why would we have pains in just one place instead of the whole body? There are muscles around your knee that are tight causing it to be in that pain. You can free up your thigh muscle to get relief to the knee sometimes, other times you need outside help in getting them released. Here's how to free up your thigh muscle for your relief:

Thigh muscle:

Sit on a chair with your leg partially extended to where it feels comfortable. Wrap both hands around the muscle about 2 inches behind your knee. Press in with both hands and hold a firm pressure on the muscle. Now relax, take a deep breath and exhale, then remain this relaxed. After 20 seconds or so you should feel the muscle releasing. As it’s a big one it’s going to continue to do so for about a minute or so. When you no longer notice any releasing happening, slowly slide your foot back up to the chair, then release the pressure on the muscle but continue resting your foot by the chair for another 30 seconds.

In doing this have your thumbs pressed straight down into the top of your leg as well, that muscle is key to your relief.

Yeah it's probably just growing pains nothing to worry about they come and go sometime when I wake up in the morning I have that same pain in my knees and later they go yeah it is most probably just growing pains.

It is may be because of your bone now you are groing so new blood will come to your body your body is developing now