Hi Becky,
Welcome

I think even after surgery it's best to keep doing some kind of posture/body work as a home stretching program.
Scar tissue can be a problem, some people seem to "grow " it more than others. Or you could just be slowly sliding back into problem postures or having sticky fascia problems.

Can you ask for an expert PT evaluation and maybe a few sessions to head this off early?

I notice when my arm pit/pec minor muscle } gets tight my elbow gets a bit sore.
Sharon Butler has a good book about fascia {explains how it gets "sticky"} and stretches , also a website.
{info posted in the sticky link below}
There are links, info and articles in our useful sticky thread-
Useful
http://neurotalk.psychcentral.com/thread84.html
drs & PT
http://neurotalk.psychcentral.com/thread135.html

Those threads have a lot to absorb- it might save you a lot of searching. If you have any questions, just ask.