Hi mountain769 ,
I have read your question ,
Generally hearing heart beat in ears & skin darkening under eyes are due to reasons like weakness , sleeplessness
& reduction in lung capacity .In your case as you smoke these maybe the reasons .
is always injurious to health since respiratory system plays a vital role in our body functioning & such symptoms show problems in respiratory system.
Keeping your age in mind , it is really important to reduce your habit of smoking and i suggest you to quit it eventually .
If these symptoms persist i suggest you to consult a nearby physician for further medical advice
Wishing you a good health,