5 months...asthma?

I have a 5 month old. A month ago he had a bad cold and was on antibiotocs...he has been fine in that sense but his breathing is not right. The last few days hes wheezing heavily gets breathless easy and is a little congested. I went doctor who said his chest is clear and that it could be teething. Should i go and see another doctor or ride it out? I have asthma and we both have eczema both of which points it more to asthma