My son had the same thing, I took him to his pediatrician and sent him antibiotics (twice) , which didn't work, I took him to another doctor and gave him a different antibiotic that finally worked, but my son was coughing like for almost two months, so i think you should take your son to his doctor, and if he started daycare not long ago, that is normal they get sick all the time.
Thankyou for the input it was very helpful. I have made an appt. with his doctor and can't wait for the results! Thankyou for sharing with me. I don't feel so alone now.