Dogs can have allergies too. Take her to a second vet, bring your vaccination records (bc kennel cough, mentioned above, is very serious & always possible.) Have her checked out there too.
Also, observe how/when she does it. Is it when she's excited? Eating? All the time? Running around? Inside or outside, or a particular room? Is it a reaction (she sneezed when you surprise her)? Can you get her to do it? Is it different for different things? Write all of your observations down & take it to the vet. If you can get her to do it, i.e. get her excited so she starts sneezing, do that at the vet's.
Last & not-so-common but worth mentioning, sometimes on animals the flap between the esophogas and trachia (i.e. the food & wind pipes in your throat) can be loose, causing wheezing especially after exercise. Again, not common but worth mentioning, I know a couple dogs & horses with that problem... its not too bad but one was bad enough that they required surgery to pin the flap better, so it could exercise without choking.
Sorry I know its a long read, but basically the more info you bring to the vet, the better they can help. And, if its not hurting her quality of life, maybe its just a quirk!
Also, observe how/when she does it. Is it when she's excited? Eating? All the time? Running around? Inside or outside, or a particular room? Is it a reaction (she sneezed when you surprise her)? Can you get her to do it? Is it different for different things? Write all of your observations down & take it to the vet. If you can get her to do it, i.e. get her excited so she starts sneezing, do that at the vet's.
Last & not-so-common but worth mentioning, sometimes on animals the flap between the esophogas and trachia (i.e. the food & wind pipes in your throat) can be loose, causing wheezing especially after exercise. Again, not common but worth mentioning, I know a couple dogs & horses with that problem... its not too bad but one was bad enough that they required surgery to pin the flap better, so it could exercise without choking.
Sorry I know its a long read, but basically the more info you bring to the vet, the better they can help. And, if its not hurting her quality of life, maybe its just a quirk!