Warning Message

So, I’ve been building my own WP theme/template, and I’ve run into another problem:

Warning: Cannot modify header information – headers already sent by (output started at /home/graceann/public_html/wp-content/themes/and again and again/functions.php:2) in /home/graceann/public_html/wp-includes/pluggable.php on line 881

Can someone please explain this and how I fix it? I’m terribly confused. :-/