The vet could not find anything wrong with Mr. Jack. Jack wouldn't even cough for him. His coughing has really decreased since yesterday. The vet thinks what I first thought and that is that Jack may have had a piece of food caught in his throat. He thinks it is now gone and maybe his throat is now sore and that's what is causing the coughing today.
He checked his lungs, eyes, nose and ears and everything seems to be fine.
I probably should have just waited and not taken him to the vet, but I feared he had a virus.