Hi. My Son Is 9 Years Old And Just In

Hi. My son is 9 years old and just in the last several days has developed a cough. He has medicine both over the counter and prescription cough medicine but nothing seems to help. He doesn't have any other symptoms. No fever, no runny nose, nothing. Any suggestions? I will be calling to make an appt. tomorrow for him with our family doctor but thought I would research to see what I could find.