My son has "whooping" noise when coughing. 4 years old, had 4 dtap shots so far - up to date. should i be worried? no other health conditions.

Visit pediatrician: While your son has had his immunizations, it sounds like he has a significant cough. It may be just part of a viral syndrome and not anything to worry about, but it could be a number of other things like bronchitis or pertussis (in spite of being fully vaccinated - look up "herd immunity" if you are interested in more). In any case getting him examined by his physician is prudent.