Ryley has just started at a new day care and gets so excited when we drop him off and pick him up that he pulls so hard on the leash that he chokes. Now he has developed a cough and gag whenever he gets excited or exerts himself - like during play time. We have since bought him a harness with the D ring at the chest and I really don't suspect kennel cough so could he have an injured trachea that requires a vet visit? Anyone ever experience this and if so, what did you do?