Knee makes popping sound?

My question is I was kneeling (on my left knee) then it popped and I felt a sharp pain for like 1 second, It hasn't hurt since, its stable, bendable and not swollen, but now ever once in a while it will make a popping sound when I bend it, just like my other knee, did I reall hurt it? I know its not a ACL tear, (cause I know what that feels like) but what could have happened, I really don't want to go back to soccer and hurt another knee when it could be a simple fix now.