For laurenspeak:
Hello -
The left-sided
pain you describe is almost certainly not heart related, even as aytpical
pain goes. It is retrograde (runs backward from an extremity to your chest) and your description strongly suggests you may have developed a neuromuscular or orthopedic/neurological injury due to the unbalanced strain on your right side by holding baby. This could be as simple as simple strain or could be more complex, such as thoracic outlet syndrome (nothing life-threatening, but something which can cause this sort of symptomology and is many times due to postural change -- like holdng baby -- when it's not due to trauma). A neurologist would probably be your best bet as a specialty consult, as the
pain sounds like it is distributed along a nerve pathway running from your right extremity back up to just about where the thoracic outlet is located. This makes sense and is often treatable by changes in postural habits, physical therapy and/or home exercises. Rarely, it is corrected by surgery. It's worth looking into.
Your right-sided
pain also sounds unlike even atypical heart
pain, but more like possible reciprocal (compensatory)
pain possibly from the strain on the left side. You may have had some inflammation of the cartilage between your ribs on that side prior to this and it may have become irritated again.
I hope this is helpful to you. Good luck with this and follow up with us here as needed.