A very interesting article. We tend to fear pain but like other biological reactions it has a very important role to play in our well-being. In fact, if a child is born without the ability to feel pain (caused by a genetic defect) he or she is very unlikely to survive to adolescence due to the fact that he or she could have a serious injury or illness and not realise until it's too late.
We have a negative reaction to pain, but that is simply because the pain signals need to be aversive enough to cause us to react. Without reaction, something very serious could happen, so an animal that doesn't react negatively and seek to reduce pain is unlikely to survive very long.
Like many physiological reactions, pain can be brought under conscious control. That is the theory behind hypnobirthing, in which the brain is convinced to feel and accept the pain of childbirth without allowing it to produce the sense of panic and fear that that level of pain would normally produce. The flight or fight response that pain usually creates is inappropriate in childbirth and can produce too much adrenalin and cortisol which increase the perceived level of pain, making it more difficult to cope with.
If a woman is coached to understand that the pain is real but also perfectly normal, acceptable and necessary then hopefully she will be able to calm her body's flight or fight response and thus the pain takes on a whole new feeling -in fact most women who successfully hypnobirth say that they felt no pain. That's not in fact true. If you measured everything on a purely physiological level you would probably find that a hypnobirthing woman is producing the same electrical signals as other women. Thus in a purely biological sense they are feeling pain but their brain has reinterpreted it so it feels more like a strong sensation.