thanks for your question i completely understand your question actually in chronic bronchitis cough will remain either less or more through out but if cough with expectoration , that too if sputum is yellow or green in colour or foul smelling that means there is a secondary bacterial infection which happened it can be associated with other symptoms of fever or breathlessness better to consult a pulmonologist who can start you on antibiotics it will be better if pulmonologist will send a sputum culture and senstivity so that if inspite of the empirical antibiotics if cough and purulent sputum remains accurate therapy can be started cough in chronic bronchitis is a mechanism to clear out excess of secretions that is a normal phenomenon in bronchitis that protects airways to get damaged due to retained secretions , which can lead to infections exact treatment for chronic bronchitis is inhaled drugs that will cause bronchodilatation and ease your symptoms consider consulting a pulmonologist and disscuss the above treatment and investigation modalities thanks feel free to ask more questions