A OR B EITHER ONE I THINK:)
Well one would be constipation, when you are constipated you tend to get lower and upper back pain. Your liver and or kindness can cause back pain, a strained muscle or popped out disk can cause back pain. Alot of things can..
The nervous system in one's body sends signals to the muscles to contract in order to move or perform a task like walking. The respiratory system sends oxygen to the muscles in order to provide energy for those actions
