Email Address Compromised

I am not sure what you actually expect Norton to do.  Assuming you download your messages to a local email client (as opposed to webmail) and your email is not using an encrypted port (it probably is, as most ISPs now require it), Norton could flag known spam to keep it out of your inbox.  A sudden surge in spam is likely due to spammers having obtained your email address as a confirmed live address, which can happen in a number of ways, such as you replying to a spam message (even to opt out) or viewing an image in a message.  There really isn't anything Norton can do about that.  Your email service provider can also block known spam if you configure your account to do that.  It doesn't sound like your account was compromised, unless there are other details not mentioned in your post.  Essentially, there is no method to prevent spam from being sent to your address;  all you can do is set up your account and email client to put it in a junk folder rather than your inbox.