Yes, I think you need to see your doctor.
You could have separate issues - a muscle/shoulder issue and a cardiac issue, but you definitely need to get both checked out.
There are a number of minor cardiac conditions that could be causing the irregular heart beats, but you need to get that checked. It could indicate something more than minor, too.
If you need it, we have heart forums -
https://
www.medhelp.org/forums/Heart-Disease/show/72
https://
www.medhelp.org/forums/Heart-Rhythm/show/92
Get it checked, though. Let us know how it goes. :)