Why Are there Differences in Pain Tolerances?

This paper deals with the many different reasons why a quarter the population are stotics, another quarter are weak, and the rest of the half are somewhere in between. It has the psychological reasons and the scientific reasons(like the val and met genes, and the mu-opioid). There are probably some grammatical mistakes, and I apoligize for this.
Pain, according to Coach Eric Anderson of the University of California Irvine, is
a subjective, psychological phemonenon. There are two types of pain, clonic and chronic.
Clonic pain is the type that comes on quickly and dies quickly, as well.…