Hello You are having cough with dark brown to yellow , mucus ( expectoration or phlegm ) with rattling cough , running nose . You are habitual smoker. These symptoms may be due to these possibilities , these include: 1 Bronchiectasis , all these symptoms are characteristic feature of bronchiectasis . However this may be mild to moderate as : ---Mild Rattling cough producing sputum after cold only. sputum production less than 10 ml /day. change of position may cause sputum production. May cause mild hmoptysis ( as in your case dark to brown color sputum ) Well patient ( as you don t have any tiredness or fatigue , or fever ). ---Moderate Constant rattly cough Sputum production of 10-150 ml/day. Sputum production most of the time Occasional hemoptysis may have foul smelling breath. Usually well patient. Get in blood for C B C , E SR , CHEST x ray shows linear atelectasis , dilated and thickened airways & irregular opacities representing mucopurulent plugs. 2 Allergic bronchitis complicated or uncomplicated with allergy . 3 Tuberculosis as this may be the another cause because after long duration patient don,t feel low grade fever ( common in PTB ). In my opinion consult a CHEST & TUBERCULOSIS or PULMONOLOGIST and get opinion. Hope this will help you. Good luck.