If you don't hear any wheezing and this doesn't happen all the time, my guess would be the puppy is dreaming. If there is any other indication of something that could be wrong, a vet visit is always best.
Snake Vom Eselspfad RN CGC (AKA Raina) 3/5/08
Pyrate CGC 4/1/03-5/16/12 RIP
Too many to list waiting at the bridge but remembering them all