Is his cough loose or is it a tight cough? (did that make any sense) he may be congested or even have a touch of bronchitis sometimes strep can cause a chest cold I hope your little feels better..
my mom has been really sick with strep throat, and Bronchitis and pneumonia, she is on her second dose of medicine and had to go back yesterday for 2 shots also.
I know it is rough having a sick baby.