There are people who are unable to feel pain

They are very small, but they are there: people with congenital insensitivity to pain with anhidrosis (CIPA). The latter indicates that they also are unable to sweat.

Congenital disorder CIPA blocks all pain, including heat, cold, and the urge to urinate. Because of this, such people often hurt themselves, most often the hands, feet and mouth. Due to the inability to sweat, they often become victims of hyperthermia, ie overheating of the body, which then can lead to mental retardation.

People with CIPA very little - in the US it documented 84 such the only one in Japan - about 300, and in New Zealand - only two.

via factroom.ru