Hello and thank you for using this site to help you. I am sorry an expert was not available sooner and I am sorry that Major is not feeling well.
Sometimes the dental chews can cause an obstruction if they chew off a big piece. This would cause vomiting but you would also start to see a sudden lack of appetite, some diarrhea or change in stool and lethargy.
You may be seeing this due to the dog food change or a virus , and you can wait it out and fast him for 24 hours then start a bland diet of boiled chicken and cooked white rice .
But if you think there is distress in breathing, then do not hesitate to have him seen, especially if he is getting over kennel cough a sometimes this can lead to a bacterial infection of the lungs where antibiotics are needed.
I would be keeping an eye on his vital signs such as gum color, capillary refill time and temperature at this point to determine if you do have an emergency on your hands. I will direct you to a link that takes you through this.
If the gums are pale or white, bluish or gray, please don't hesitate to seek Vet care immediately.