This song is about someone who wants to be a hero. The lyrics are saying that people were saying that LOVE or a HERO would come and save them, but there was no hero. During the beginning "I am so high, I can hear heaven, Oh but heaven, no heaven don't hear me" is saying that he wants to be a hero but god isn't listening to his cry. "Now that the world isnt ending, its love that Im sending to you. It isn't the love of a hero, and thats why I fear it wont do." This man wants to be a hero to save his lover from whatever the problem is.
I think that a hero is a person who wants to save the people they love. They need a villain too be a hero, or they need something to save the loved ones from, a natural disaster, a villain, etc. A hero is someone who helps people with payment, and usually they got bit by a spider or something like that to make them a hero. The song Hero by Nickelback is saying that he wants to be a hero to save the one that he loves but heaven is not hearing his cries about being a hero.