Hello, and thank you for your medical question on e Health Forum.
From the description it seems that your symptoms could be due to sinusitis and post nasal discharge.
The description of the chest pain could indicate a lung infection.
You might benefit from a physical examination as well as investigations including a chest Xray, A CT scan, a sputum test, blood tests etc for a proper diagnosis.
Smoking 3 packs a day is very high and can predispose you to develop Chronic obstructive pulmonary disease, that can reduce your lung function even further. You might consider cutting it down or completely quitting it. Nicotine gum can be used to help you quit smoking.
Your symptoms might improve with treatment with medications like clarinex or Benadryl, AND, antibiotics to clear the infection.
You might consult a doctor for further evaluation and treatment of your symptoms.
I hope this helps.