This important muscle causes flexibility issues in your chest. It can cause back pain and it can cause shoulder pain. It also has been known to cause a shoulder injury.
The major muscle that I’m going to discuss today is your PEC minor or your pectoralis minor muscle. This muscle goes from your Coracoid process to your scapula also known as the shoulder blade and then connects your third fourth and fifth ribs.
The Pec Minor is known to cause so many ailments in people and it's often overlooked. You might not even know that this muscle even exists. I personally didn't realize this muscle was so stiff on myself until someone tested it on me. If this muscle is very tight to you then this is forcing, you into a bad posture position. With round shoulders, it can cause a shoulder injury by decreasing the space of your shoulder movement and putting additional wear and tear on your shoulder joint.
We are very prone to having a tight PEC minor just because we have a very sedentary lifestyle and tend to round our shoulders when we're doing activities of daily living. This muscle can easily get very tight on many of us and it's such an overlooked muscle, so you really want to focus on stretching your PEC minor.
The actions of this muscle that is connected to your shoulder blades is to bring your shoulders forward or backward. It also tilts your shoulder blades vertically.
This muscle is important because, as you raise your arms up over your head your shoulder blades are supposed to rotate accoridngly. If this muscle is very tight, you can’t rotate your shoulders to their full extent and you are jamming the space of the shoulder region. In all, this will cause a lack of mobility.
Because you're not getting the rotation that you need you are putting yourself at risk. This risk pertains to any exercises or movements that utilize your shoulders. So, the bottom line is that you want to really stretch this muscle! You need to stretch this muscle every day as long as you're not in pain doing it.
Well here's what you do and it's simple. Go into a corner of a room and then put your hands and arms up on each adjacent wall. You're going to raise your elbows just slightly higher than your shoulders, and gently lean forward while your feet are planted. You should feel a stretch in your Pec Minor. Stretch out the muscle for 30 seconds at a time and at least 3-5 minutes of stretching per session. See picture below for example.
Even though this muscle group is on the smaller side it is still very powerful and needs this kind of attention. You can do this stretch each day. Doing these on a daily basis is going to help to improve expand your chest, and decrease your back and shoulder pain.
This stretch is going to help you improve your posture.
All in all, this is why the PEC minor is the best muscle to stretch for upper back pain and to acheive a natural posture.