An upper respiratory infection, along with allergy (bad cough that you caught from your son) is one of the common triggers of asthma attack in predisposed person.
Blocked ears are experienced always when there is a nasal stiffness and nasal discharge (runny nose and nasal congestion are symptoms of upper respiratory infection, like sinusitis; hay fever sufferers are prone to chronic sinusitis and also, this ear blockage can be result of allergic reaction causing the ear lining to swell, too).
Symptoms of asthma, usually start to get better between three to seven days after starting treatment with qvar preventive inhaler.

I have now be diagnosed with a chest infection, the doctor said the clicking is crackles. However, I have realised that I have been trying to cough the wheeze away, could this over-coughing be causing the crackles? The more I cough the worse they seem to get!

Each crackle heard during exhalation represents an abrupt closing of a single small airway.
Bronchitis and emphysema can cause end-exhalation crackles.