The story suggests you have got exerbation of Asthma with probable bacterial infection. My advise will be to see a chest Physician. Ventiolin(Salbutamol) is brocho dilator.It will not work much on its own as becauseyour air tubes can not dilate any more.Inside your air tubes are swollen due to inflamtion and it needs steroids, also you need antibiotics for infection. When some one caughs up discoloured sputum like green or yellow it suggests usually bacterial infection. You need to stop smoking. You should have chest X-ray lung function test and examination of sputum. Idially you should use two medications one is Ventiolin only when you feel tightness inthe chest and the othe one is steroid inhailer which you should use regularly twice daily. The chest Pysician will give you properlong term advise. You are only young smoking leads dangerous condition of the lungs known as COPD .