My dog continually is trying to clear his throat/sounds like he is going to throw up help!!!?

My dog continually is trying to clear his throat/sounds like he is going to throw up. He drank a lot of water while at the lake yesterday when he was swimming. Is this anything for concern or will it pass? He is a year and a half old pit bull, and just loves to swim but he ends up getting a lot of water in his mouth. It doesn't sound like kennel cough which he has already had and been vaccinated for.