When you buy a pure breed puppy for $150 from a web site - it is a puppy mill dog. Your dog probably was not vaccinated, wormed, or cared well for. When a dog is coughing, it is SICK and probably very contagious. Letting your puppy run at a dog park, drink water from communal bowls, and lick other dogs while coughing is completely irresponsible. My dog is sick now and if I could I would collect a vet fee from you for every dog you made sick at the park. Please read a basic guide for disease and responsible dog handling. You puppy is the most at risk - germs like PARVO will kill your dog if you aren't careful.