This type of pain is the most universal pain of them all! The causes of back pain are infinite—from posture to excessive lifting to trauma/accident. Back pain generally exists in either the upper back or the lower back, where both areas extend to affect other areas of the back, neck and shoulders.
Low back pain can involve the muscles along the spine (paraspinalis), the deep muscles (quadratus lumborum / psoas) or the side muscles (latisimus dorsi). This pain can also be caused by your hamstrings in the upper back of the legs.
Upper back pain, however, often involves muscles attached to the shoulder blades. Massaging the shoulder blade areas often brings relief. Some muscles tend to shorten and pull the shoulder blades outward causing strain to the other muscles attached to them. It is a "balancing act" to bring this structure to a healthy "neutral" place. Although massage can help in one session, multiple sessions over time are especially effective in getting results.