Hi am 26 years old and I am experiencing fluttering. When ever it happens I cough. I usually feel it if I'm bending down, or sweeping or doing simple things. It even happen at times when I'm just sitting at my desk at work. I went and saw a cardioligist and he placed a holter monitor on me for 24 hours and he said that there was nothing unusal, but I know what I'm feeling can't just be my mind. The fluttering don't happen everyday but it happens, the only thing I can do is cough.
stop smoking -- it isn't related to the fluttering but I still feel I should tell you to stop.
I get the fluttering or vibration questions a lot and they are almost never related to heart rhythms. I am not able to give a solid answer as to what causes them, but as long as it feels like it is surface level (around your nipple) it is usually not heart related. Sometimes muscle with contract (fasciculate) and cause a vibration or fluttering sensation, but you can usually see this as a muscle twitching.
If you feel like the fluttering is inside your chest, this can sometimes be related to premature beats from your atrium or ventricle. The best way to figure that out is with holter monitor if it happens everyday or an event monitor if it only happens a few times per month.
I hope this helps, thanks for posting.