The mid back is the area between the base of your neck down to just above your waist. The ribs are attached either side of the mid back (thoracic) area vertebrae and angle down from the back and round and up to the breast bone in your chest.
If you have issues with movement in your mid back that can affect the way the ribs move and also a nerve travels between the ribs so that can be irritated too and give rise to tingling, pain or numbness anywhere along the rib from front to back or give rise to pain right through your chest.
The shoulder blades have muscles leading to the mid back so using your shoulders incorrectly can cause pain in the mid back too.
You can be born with what is called scoliosis, which is when the mid back curves sideways, often in two places and affects posture.
Sitting badly, particularly when we have an office job and we slump too often, can cause pain in the back or pain that radiates from the back, between our shoulder blades, round to the front in our chest.
It can hurt to breath on occasions as the ribs move on respiration and sometimes our mid back curves as in a scoliosis and that puts uneven pressure on the joints in that region, which can cause pain.