Based on the history you provided, below are the possible causes for your dog’s coughing. Please click on the links for more information on these diseases. If you still seek further information, please refer to our Ask the vet page to ask a veterinarian 24/7.
Complications from Heart murmur
I had her checked out for heartworms and they called me today and said it was negative so that’s why I’m wondering what else could be wrong