My Dog Sneezes A Lot. I Never Notice This Before. He Was Recently In A Kennel For A Week But I Don't Remember Hearing The Sneezing Until About 3 Day Ago. Could He Just Have A Cold?

It is possible your dog picked up kennel cough or another upper respiratory infection while staying at the kennel.  Most kennel cough is mild and self-limiting.  If your dog develops nasal discharge, a cough, loses his appetite, and becomes lethargic he needs to be seen by a veterinarian for treatment.
You can try Benadryl at home--the dose is 1 milligram per pound of body weight given by mouth 2-3 times a day.  Do NOT use the Cold and Sinus variety--it needs to be plain Benadryl. 
If he is still sneezing after 4-5 days I would have him examined by a veterinarian.