After much research, doctors have now determined that the brain of a patient with chronic back pain may age as much as 20 times faster than normal. The reason is because chronic back pain is said to shrink the brain, sometimes as much as 11%. The part of the brain that it affects is the part that helps us with memory and processing information also referred to as the gray matter of the brain. Research also believes that the brain goes back to its normal size when the back pain goes away.