Its Weird when I cut down on Smoking before I actually quit
I also had chest pains as you do like a burning sensation and tightness. I was so worried I went to an ER and they ran EKG, Blood Work and Xray and said it wasnt a heart attack (Thank God).
Got my doctor to set me up with a Stress test for my heart and results came back as working normal. (I've Quit for 8 days now)
I would always suggest to speak to a doctor or if it gets really bad and you get really worried go to the ER if needed.