have two situations. My first situation is my knee. At random times my knee will lock up and I have to pop it so I can go on with what I m doing. My knee also hurts when I m sitting awkwardly, or doing something physical. Also whenever I bend my knees, they will pop. My second situation is the my left ankle hurts. I always kinda hurt it when I walk somehow. Even if I don t it still hurts. At night is when it hurts the most. When I lay down in bed, and hang my leg off my bed, and relax, I will get this really bad pain. If it helps.. I m a 13 year girl. Don t do sports often, but do once in a while. I also broke my ankle when I was 7.