Congratulations!!! You sound like you came through surgery quite well!
When they cut through that sternum and splay you open to do their work, sometimes they lean on you too hard! Many people have complained of that feeling you describe. It should certainly dissipate in time. How much time kind of depends on how much they were moving you around. Everyone is different. There might be some bruising show up. Then it will just run its course.
If the sensations change, and you feel like you may have pinched nerves somewhere, you might consider some massage therapy....but soft massage, not deep tissue right off the bat. Oftentime people's shoulders and arms feel the event for awhile. Anything beyond uncomfortable, you should check with your doctor, of course.
Welcome to this great community. Please feel free to share your experience with us, ask any questions you might have, and get to know this pretty darn nice group of people!
Marguerite