Pain is an unpleasant feeling which may be associated with actual or potential tissue damage and which may have physical and emotional mechanism.
According to the International friendship for the Study of Pain (IASP), one should distinguish between pain and nociception. The sound "pain" comes from
the Latin "poena" meaning a fine, a penalty.The word "pain" is a subjective experience that typically accompanies nociception, but can also arise without any incentive, and thus includes the
emotional response. Nociception, on the other hand, is a neurophysiological term and denotes particular activity in nerve pathways. It is the broadcast
mechanism for physiological pain, and does not describe psychological pain. These pathways pass on the nominally "painful" signals, though they are not
forever perceived as painful. Although pain can be associated with tissue spoil or inflammation, this is often not the case.Despite its unpleasantness, pain is a dangerous component of the body's defense system. It is part of a rapid warning relay instructing the motor neurons
of the middle nervous system to minimize noticed physical harm. Lack of the ability to experience pain, as in the rare condition congenital selfishness to
pain or Congenital Analgesia, can cause assorted health problems.The two most widespread forms of pain reported in the U.S. are headache and back pain. Pain is also a term purposely used to denote a painful uterine
contraction occurring in childbirth.