Someone who enjoys pain is called a masochist, according to Dictionary.com. Masochism is defined as finding pleasure in pain. Masochistic is an adjective used to describe someone who is gratified by pain, and masochism is considered an abnormal psychological condition.
Masochism is often used to refer to the practice of receiving sexual pleasure through pain or humiliation. Sadism is the opposite of masochism and refers to finding pleasure in inflicting pain on others. Sadomasochism refers to an exchange of power and pain between two people, usually for the purpose of sexual gratification. Masochistic behavior can be mild and mostly symbolic, or it can involve serious pain and dangerous situations.