Sounds like Kennel Cough. Especially if she plays with other dogs, or was recently kenneled. She may need antibiotics.
Hi
Peek is right, your dog should see a vet.
Years ago I gave our dog human cough medicine but only after the vet recommended it.
lonewolf
You shouldn't give your dog any cough syrup. The dog needs to see a veterinarian to find out what's causing the cough. It could be something simple, or it could be very serious.
How is your dog feeling now???