Worldwide, more than 1.5 billion people suffer from chronic pain. In the US, it impacts about 100 million adults, which is more than the number impacted by diabetes, heart disease, and cancer combined.
It can be a challenging condition to treat because while some chronic pain is associated with an injury or disease, in other cases there is no initial event (such as a back injury, infection, arthritis, or cancer) that caused the pain.
