my artist name is different than my profile name, i'm just kind of too lazy to make a new one.
if you want to keep your music but change your name, it's really time consuming to change your artist name. especially if your music is available on a lot of sharing/selling sites. i've changed my artist name once, and it didn't change anything because nobody knew who i was anyways.
so really, it's up to you.
and your artist name should give the listener a general idea of what to expect from your music, and it's interesting enough to make people want to check your music out. (just my opinion)
edit for second question, yo