Purposes of Pain
Many would feel that it would be a great thing not to feel physical pain. Pain though, is a way ones body tells it that something is wrong. An individual touching a hot stove would feel instant pain, forcing them to pull their hand away before causing too much damage. Pain tells you when you've pushed too far, when you're in a situation you need to get out of and when something is terribly wrong. If you step on a piece of glass or bang your head too hard, you know you need medical attention. But what if you never felt it? Congenital insensitivity to pain and congenital insensitivity to pain with anhidrosis (CIPA) are part of a family of disorders called HSAN, which stands for hereditary sensory and autonomic neuropathy. People with congenital insensitivity to pain and CIPA have a severe loss of sensory perception. They can feel pressure, but not pain, so they are likely to injure or mutilate themselves without meaning to. They might know they slammed their hand in the door, it just doesn't hurt.
Most people are not disabled by nociceptic pain, which is pain caused by injury or trauma to the body's tissues, but rather by chronic pain. Indeed, about 70 million Americans are partially or completely disabled by chronic, debilitating pain, according to the National Pain Foundation. And despite advances in pain treatment, many people encourage themselves to dismiss or ignore pain. Unfortunately statistics for Australia are more difficult to come by.
Source: http://ghr.nlm.nih.gov/condition/congenital-insensitivity-to-pain-with-anhidrosis