Warning: Cannot modify header information

Hello fellow forum members,

I’m new to WordPress, and I’m having a few issues with some changes I made last night. I’ve installed WordPress and it’s been working fine for months. I decided I needed to backup the database, so I went through Godaddy’s backup service for the SQL database, but couldn’t remember the password to logon. I went through their password changing process, and was able to backup the database. I didn’t think about the fact that the password would need to be changed in the wp-config.php file, so the site said the blog had been deleted. I went back into the wp-config file, changed the password to the new one I created, and uploaded it through PHP. Now, when I access the site, I get

Warning: Cannot modify header information – headers already sent by (output started at /home/content/a/g/e/agentgambell/html/wp-config.php:63) in /home/content/a/g/e/agentgambell/html/wp-includes/pluggable.php on line 770

any and all advice is very much appreciated.

Thanks!