How is your puppy acting , is his nose and eyes clear or does he discharge ? and how about his gums ,how do they look ? Puppy can get pneumonia and there are other health issues that can affect their breathing , so it's hard to say what wrong but you really need to have a vet check your puppy out. OOPS I did not mean post that two times.
http://www.pethealthnetwork.com/dog-...an-do-about-it