The way child had fever runny nose cough… it all is like viral fever
. Two points may have to be noted here…
can worsen cough so should be using alternative like paracetamol…
Xray chest normal may suggest throat infection
or adenoid or airway disease… look for earache crankiness etc.
Get a blood test
done to get it normal cbc and mp test… also a throat swab test for strept…
I hope this answers your query. Get back for any further details.