What’s up man?
I’m not a doctor, but;
Pec minor attaches to shoulder blade. If your upper back is “messed up” and not supporting your shoulder properly your pec could easily be jumping in to hold your arm in place. This isn’t ideal so, you could get pain in your chest.
I first heard about this when a super strong overhead presser with back issues talked about a sore pec minor after some overhead work.
Shoulder and upper back stability issues are super common on this board. Often they start after a blow to the shoulder or damage to nerves around the neck or arm pit.
If any of this sounds like you, check out
https://t-nation.com/t/help-with-scapula-protraction-weak-serratus-trap/248845/9
https://t-nation.com/t/two-chronic-injuries-that-just-won-t-go-away/248329/18
And also all the TNation articles about posture and face pulls.