SHOULDER & UPPER BACK DISCOMFORT
We can condition our muscles over time to be stronger or more enduring through exercise. The reverse is also true. We can decondition our muscles over time. For your shoulders, upper back and thoracic area this can be a result of, but not limited to, incorrect posture while sitting on a desk or the weight of your increased breasts during pregnancy. After giving birth this hunched forward posture is further exacerbated from feeding the baby for several hours a day, whether you are breast or bottle feeding, bending over to change nappies and the position you carry the baby or your toddler (you will probably notice that because you favor carrying them on one side). Unfortunately, during these times, you may also experience discomfort due to working from home or homeschooling.
As you may be spending a considerable amount of time during your day in these postures, your body is under a constant low amount of physical stress and never gets a chance to heal. When newly postpartum this is compounded by stress and a lack of sleep, which heightens inflammation.
Working on your shoulder and upper back flexibility as well as strengthening your core should help you notice a significant difference; alleviate any pain you are experiencing and help you breathe better.
The upper body is also where many of us tend to hold tension from stress and anxiety. Therefore, focusing on this area may help calm the nervous system / stimulate the parasympathetic nervous system ie your rest and digest mode.
FLEXIBILITY
Muscles that cannot extend to their full length and are under a constant low pressure will tighten and become weak, it is important to lengthen these muscles allowing them to regain their full range of motion. This will thereby improve physical performance.