Shrinivas, First, let s lessen your anxiety. Poking brief and rapidly disappearing sensations are rarely related to your heart. Further, your heart and cancer are rarely tied together unless we re talking about some of the treatments for cancer. You have rightly turned your attention to the most important risk to you, smoking. Search Yul Brynner smoking on YouTube for some encouragement. No medicine is more effective than your decision to stop smoking. Mindfulness and meditation are good, non-medical aids as are talking a friend into quitting with you and exercise, just daily walking. Good luck.