I am a smoker not heavy but it goes to 2-3 cigrette a day . I started smoking past three years , now i want to loose this habit ,but still sometimes i have pain in my left part of the neck its not regular but still it bothers me sometimes because it last whole day , to get releif i have to make some neck stretches etc I having this problem from last 6 months, Let me know that its not serious and what precaustions should i take.