Tore my pec a long time ago, stopped training some time afterward, and now I have recurring back pain behind and around the pec area (but not the pec itself). When I look at an anatomy chart, it feels like it would be the infraspinatus. It feels like it juts out back, behind me, and is painful to rotate my shoulder all the way back (which feels like the shoulder blade is making contact with this muscle). Unfortunately, having shoulder blades back is both good posture and mostly in line with good lifting technique. This directly hinders breathing.

When I squeeze my shoulder tight into my body, all pains go away at least a little. When I flex whats left of my pec, I dont feel this infraspinatus pain at all.

Which leads to my question, how to manage this type of chronic injury? Do I make my pecs really strong (to mimic the painlessness of a flexed pec), or do I work the painful area/stabilizers (in this case the infraspin: face pulls or band pull-aparts, something like that)?