What does the human body produce naturally that we often take medicine such as oxycodone for?

The human body naturally produces endorphins, which are pain-relieving chemicals that help alleviate discomfort and promote a sense of well-being. These neurotransmitters bind to the same receptors as opioid medications like oxycodone, providing pain relief. However, when pain is severe or chronic, the body's natural endorphin levels may not be sufficient, leading to the use of medications to manage pain effectively.