I am a smoker continously smokes whole day. I smoke nearly a pack of cigarettes per day some times even more I some times feel pain in lungs n heart I don't know what is the reason n where the pain is exactly in heart or lungs but some time I feel chest pain I tried to quit smoking but I failed. And I am a seafarer so I must be fit enough and able to survive conjusted n enclosed spaces but I feel suffocated n feels very uncomfortable to breathe so kindly help me suggest me what to do how to improve my health n how to stay fit how to get rid of suffocated and breathing problems ?