Pec Minor Stretch

Stand side-on to a wall and place your hand behind you against it, palm flat, with your arm lower than shoulder height, closer to hip level. Keeping that arm straight, rotate your torso away from the wall until you feel a stretch under your collarbone rather than across the main part of your chest — that lower, deeper pull is a different muscle than a stretch done at shoulder height. Keep your shoulder pulled down and back instead of letting it ride up toward your ear as you rotate. Small changes in how high your hand sits change which fibers you feel; drop it lower still if you're not feeling it under the collarbone specifically.