thanks for your query.
is there any family history of asthma and atopy?
the history sounds to me as the initiation of childhood asthma
for that you should take your child to a pediatrician
or pulmonologist for better evaluation of symptoms.
side by side you should do a total serum IgE level and skin prick test to know allergic basis of your child.
again after the age of 7 years your child should have to undergo pulmonary function testing with bronchodialator reversibility to know if there is any bronchoconstriction
against the allergen detected may be some help for permanent solution.
but as such if asthma is there no permanent solution will not be there.
all you have to do is to take inhalers and medications properly to control your son's symptoms.
another thing which may decrease such frequent episodes of symptoms is to vaccinate your child against influenza
and pneumococcal infection.
this will be of help to your child.