Endorphin
Endorphin is a group of hormones produced primarily in parts of the brain known as the hypothalamus and pituitary gland. The word comes from the combination endogenous, which means growth or arising in the body, and morphine, an opioid drug used to treat moderate to severe pain.
Usually endorphins are released in response to stress or pain and carry messages from one neuron to another throughout our nervous system, minimizing our perception of pain.