Well, this is not uncommon for shih tzu's because they have very short noses and small nostrils so can cause respiratory problems, if you find that they are struggling to breath a lot of the time then you might want to take her/him to the vet for a check up, also they can get something that vets call backward sneezing also people should be very careful not to take short nosed breeds like shih tzu's, pugs and bulldogs out for long walks in very hot weather because it can cause your dog to collapse, suffer heat stroke or even death.
