Self consciousness is a psychological phenomenon which often entails shyness and paranoia. Some scientists think that shyness can have a genetic cause, although it would be fair to say that environmental factors, such as things that happen to you as you grow up, will have a very important influence. Child abuse and other traumatic events can lead to anxiety and shyness.
It is a shame when people are too body conscious. So long as we eat well, exercise regularly and take care of our bodies, the body we have is the body we have – and we should try to be happy with how we look. For instance, I think I have quite a big nose – but I would never be ashamed of it, because it is part of who I am!