My cat gave himself the name goobies because he always sneezed. You should probably have it checked out for respiratory infection. They will give an antibiotic and suggest a distemper shot. Allergies aren't uncommon either. My cat doesn't sneeze anymore now that we have a smoke free home. Hope I could help!
You can give it rest and lots of water or milk. If you can, take it to the vet.
The Vet, that's what you can give, it might be an URI (Upper Respiratory Infection) and antibiotics would be prescribed to treat.