Some types of the body formation almost were adopted from back tribes, others again were invented new or evolved.
In many cultural spheres different forms of body modification are conducted from tradition and ritual already since the earliest centuries, which certainly haven´t spread not yet in the west (e.g. lotus feet from China, lip plate from different African and American tribes or the mainly in parts of Asia or Africa occurring cranial deformation).
The reasons to procure pains to the own body are so varied, as there are people, who decides for it.
For one thing of course the piercing meanwhile is considered to be a "normal" jewellery accessory and the pains by stitching are relatively small, why here probably mostly a fashionable awareness can be cited as reason. The same also applies to tattos.
Already it looks differently by still more extravagantly deformations of the body. Of course beauty is relative and is conceived various from every humans and cultures. But also the self-experience to the own body can provokes people to expose oneself to pains or people want to symbolise a definite statement or affinity.
Another point is to shine out from the masses, to be in contrast to the rest. The piercing began with its entrance in the Western culturein in the 1980s, but meanwhile as we said it´s become mainstream and now there are developed other rarer, more extreme body modifications again and again, with those people want to emphasise their individuality.
Apart from the piercing tattoos belong to the most known body modifications. But there is as well a variety of other possibilities of extreme body jewellery.
On the following sites you can read some not quite pain-free details about the stretching of piercings, branding, cutting, implants, scarification, genital beading and suspension.