### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
Hey I have been having chronic cough and yellow mucus in my throat and nose for three weeks now. I used to smoke 1 pack of cigarettes each day but for 2 months have cut down it to less than half a pack each day. This is the first time I am feeling so. Havent had any such problem earlier. Can it be lung cancer ??? I am really tensed have taken tried antibiotics, cough syrup and nasal spray. I have been on them for 3 days. The mucus is still building up in my nose but seems to get settled in my chest as I cough real hard but very little mucus comes out.age : 21 yrs (male)Weight : 68 kghave been smoking for 4 years.

### output:

Thanks for your question on Chat Doctor. I can understand your concern. Possibility of lung cancer is very less because lung cancer is uncommon at your age of 21 years. Possibility of bronchitis is more because you are smoker. Smoke irritates airways and cause inflammatory changes (bronchitis). So better to first quit smoking. This is the most important thing in treatment. Also consult pulmonologist and get done 1. Clinical examination of respiratory system 2. Chest x-ray (to rule out lung cancer) 3. PUT (pulmonary function test) for the diagnosis of bronchitis. PFT will also tell about severity of the disease. And treatment is based on severity only. You may need inhaled bronchodilator and inhaled corticosteroids (ICS). Don't worry, with proper treatment, you will be alright. But first quit smoking. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.