Foam rolling your lats, rotator cuff, serratus anterior, and intercostal muscles can help ease your breathing as well as relieve stiffness and tightness in the back and shoulders.
Step 1: Lie on your side with your foam roller in your armpit and your arm spun outwardly. If your arms spins into lots of internal rotation, this won’t feel so great, so flip your palm up towards the sky to exaggerate your starting position, and then you can find a more neutral position as appropriate for your shoulder anatomy.
Step 2: Like a tofu-veggie-kabob gently rotating on a grill, spin your whole body gently back so that you feel the foam roller pressing into the back of your shoulder blade. Spend some time (30-60 seconds) rolling back and forth over whatever tight spots you feel in this area.
Step 3: Now spin your body (along the long axis like that rotating kabob) towards the floor. Now you are experiencing pressure on the serratus anterior muscles and the anterior part of your lat muscles. Make sure to breathe! Continue spinning back and forth for a few rotations, and then pause to scoot the foam roller one inch lower. Repeat. And then scoot the roller one inch lower. Keep slowly inching the foam roller lower until the pressure becomes uncomfortable along your rib cage, and then keep the muscle-release work above that line. There are tiny (often overworked/tight/tender) muscles between each rib called the intercostal muscles. For some people, it feels fantastic to release the tension in these muscles, for other people, it feels like they are crushing their ribcage. Move slow, keep breathing, and listen to your body.