If you feel that something is going on, the like everyone would say, ask your dr if you can go to a urologist.I'm not saying anything is definitely wrong. I am saying that you won't have peace until you get checked out.
But it's best to go to a urologist so be strong to you primary dr about it.
But you are at an age that is good to get your tools checked out. At 16 they can treat just about anything just incase something truly is going wrong.
But take it easy because the odds are that nothing is wrong.
Take care,
Irwin