The Pectorals are powerful chest muscles that are often responsible for pulling our shoulders forward, and rounding the back. Often, the Pecs may be the culprit of the tension we feel in the back, between the shoulder blades (in Rhomboids and middle Trapezius muscles).
Pec Major is the bigger, stronger, and more superficial muscle, but Pec Minor (see image) is often responsible for more problems than most other muscles in the body: Brachial Plexus Syndrome, nerve entrapment, and Carpal Tunnel.
When the Pecs get tight, they compress the nerves and blood vessels that run underneath.
We use the Pecs a good deal when moving around during the day. Our life is in front of us, so we use the Pecs to reach forward for things, to hold the steering wheel, to place our hands on a keyboard, and so on. Pecs are always engaged, and shortened.
What happens to Rhomboids and middle Traps is the opposite: We don't use them enough, so they get weak, and overstretched by the stronger Pectorals.
What is the recipe for better posture and eliminating that upper back tension?
1. Get a massage therapist to release the tension in the front (Pecs), and the back (multiple muscles around shoulder blades).
2. Strengthen the Rhomboids and the Trapezius, and back muscles;
3. Stretch the Pecs.
Here are some exercises for Stretching the Pecs that can be done anywhere.
Wall Clock Stretch
Start at 12 (imaginary clock), move your hand back to 11, then 10, and 9.
Hold each for 20 seconds.