I'm 33 and gained approximately 60lbs over the last two years (smoke too). I was hit with a bad chest cold in January - had x-rays, antibiotics, etc.. The major symptoms went away, but one issue that started at that same time was that while sitting down, I would intermittently feel my heart beat in my back, usually to the right (my right) of my spinal cord on the other side of my heart - but sometimes switches sides.
I told my doctor and he ran an EKG, but he didn't see anything out of the norm. Anyone have any suggestions? Also, I have family history of high blood pressure and one thing I've been noticing over the last year during each doctor visit is that my BP has been more like 138/90, instead of the usually 120/80 that I use to get.
See if you can get the doctor to order an ECHO, just in case.
In 2007 I was diagnosed with MVP (Mitral Valve Prolapse) which is not necessarily uncommon nor is it too problematic for most. (Although mine is accompanied by regurgitation, ruptured chordae, etc - which is not normal.) I had been complaining of being able to feel my heartbeat in my neck and head for some time and just yesterday had my first visit with a new Cardiologist. He had me turn onto my left side while laying down, then he pressed my stomach and saw the veins engorged in my neck. (Apparently this is not a good sign.)
I'm not saying that would be the case with you, but it wouldn't be a bad idea to have an ECHO done to see if there is something going on in your heart that the EKG wouldn't necessarily reveal.