What would be the cause of pain when pressure is applied to the lower and upper back, the ribs, the sternum and neck?

Hard to say: Sometimes problems with your skin/herpes can cause pain. Other causes like muscular, ribs, can be painful to touch . If pain is around the sternum and radiates to the back costochondritis would be a concern. If this pain is only reproduced by pressure it is more likely musculoskeletal. However with all chest pressures its best addressed in person. See your doctor.