I am not sure of your age but given your symptoms it is best to exclude a serious pathology given your long smoking
I hope those tests will be normal, and then it is likely you have house dust mite allergy
that was not helped with your smoking habit.
A skin prick test or a specific IgE blood test
can let you know whether you have the allergy.
Long acting antihistamines with nasal sprays is the treatment, and those who fail medical treatment are offered the immunotherapy