yeah i believe it's pain who makes us what we are
also i believe that it's not only for musicians
the need to write book/song/music/anything rises after pain of any kind settles down and goes out
it's a way to express your feelings very sharply
for example one songwriter was asked how he writes so strong lyrics than he wrote a song about his hardships banging his heart like a hammer that produces a song...

and the fact that there is so many arts shows you in what kindda world ya live in...