We each have a self, but I don't think that we're born with one. You know how newborn babies believe they're part of everything; they're not separate? Well that fundamental sense of oneness is lost on us very quickly. It's like that initial stage is over - oneness: infancy, unformed, primitive. It's no longer valid or real.
Some of the best art in the world is collaborative, a mix of voices that are stronger together than separate. Take the Beatles, for example. Or every great movie ever made. We like to say they're the director's vision, but really, they're huge collaborations between directors, writers, actors, even producers.