If someone has taken control over your actual email account that would work. If the perp has only stolen your name(email address) and is using another account somewhere else. Changing your own password or login will do nothing.

Your plan would be the same thing as changing the front door lock on your house, when someone is mailing out snail mail garbage using your return address across town or the country.

The IP address in the headers may give an hint as to where the stuff is actually coming from.