>>11077478The human body has something called the Endocannabinoid System that regulates things like mood and appetite. This system has two types of receptors: Type I in the brain and Type II in the body. THC bonds to the type I receptors in the brain (producing the psychoactive effects) and CBD bonds to the type II receptors in the body (producing the calming and anti-inflammatory effects).
CBD has a wider range of medical applications, and is what you should use for general pain relief.