There is a wide spectrum of severity of illness related to Reactive Airways Disease (RAD). When this is persistent, most are more inclined to use the term asthma. If your child has had the symptoms you describe, the diagnosis of RAD is fairly common.
I posted to you below, and I see some of my questions I asked you, the answer is here. My son also had bronchiolitis(rsv)and then several colds one after the other. He is 7 months. The ped. said he had RAD from what the x-ray showed but said that it could show but never suffer symptoms, or a chronic cough maybe the only symptom, may not ever have wheezing again(which he had only when he had the RSV(bronchiolitis) infection. Nebulizer treatments did not work for him. He breathes a bit rapid when he has a cold and will be very congested, nasal as well as chest, but not in his lungs..phew... Now he has been cold free for 5 days and his breathing is fine. We are going to see a pulmonologist in April on the advice of our ped. though he feels he may never really show true asthma signs. it just may be virus induced.
Maybe a pulmonary(pediatric) one could put your mind at ease. Do you have a family history of asthma? I don't but my husbands brother had it as a child as well as his son now has it and he is 3.
Ps..my son also,when is very congested with a cold, if he coughs he may vomit and brings up clear phlegm.
Hope you find some answers!!! It is scary to worry about them so young!!!