What Causes Pain?
Our ancestors thought that pain came from evil spirits or even avenging gods like Poine, the Greek goddess of revenge, from whose name we get the word "pain."
With the help of modern medicine, we now know that pain is a complicated process involving the various chemicals of the brain and spinal column. To start, electrical impulses send messages of pain from specific pain sensory nerves to the brain.
A big role in the chronic pain process is played by neurotransmitter receptors. These receptors are the things our bodies’ chemicals are stimulating when they transmit pain, whether it’s chronic or not.
When the brain reacts to pain, the signal is usually directed to the thalamus. The thalamus is a bulb-shaped object with two roughly walnut-sized halves split at the center of the brain at the top of the brain stem. It relays messages between the brain and various body parts.