Hello and welcome to HCM. Your cough seems to be secondary to your running nose. the secretions in noseare constantly trickling back in your throat and thence into your airway that is giving you persistent cough. your running nose and smell seems to be due to allergy. this allergy may be due to anything in your surroundings including dust or pollens or animal dander. Howeverit can be easily controlled with antiallergic medications. you need to meet an ent specialist near your locality.