A lack of mobility in one region of the spine which is intended to be mobile will then lead to overuse of another region of our spines that is intended to be stable such as our lower back. This is one of the main reasons why lower back pain is so prevalent.
A slight curve in the upper back is normal. A more severe curve however will cause the scapula to tilt forward. When this happens, it can cause a decrease in the shoulder joint space and lead to impingement and reduced range of motion. This will not only cause pain and irritation but will mean that overhead movements and exercises become unsafe.
Maintaining good flexibility in your thoracic spine will therefore reduce pain and improve the way we move so that other parts and joints in our bodies do not have to compensate. While it may not be the sole cause of movement dysfunctions and pain, mobilisation of the thoracic spine will be hugely beneficial to us all.