There are three songs that I have always felt described being on stage to a tee:
Lights by Styx
Blinding Light Show by Triumph
Limelight by Rush
Having been a musician all my life, and performing in front of people for as long as I can remember, I know these songs. I may not know the "fame" aspect as these bands do, but the songs always touched me... told a bit of my story, I guess.
I think Lights best describes the "why" you perform... the need...
Blinding Light Show almost hauntingly describes the view, the sounds, the feelings when you're on stage.
Limelight gives the reality - the good, the bad and the ugly.
I forgot about Foreigner's Jukebox Hero - This song is what made me add this post. I was listening to it and remembering 1981, summer after my freshmen year in high school, and all I wanted to do was play music. I didn't care about anything else. I was lucky enough to actually be playing music, onstage, every weekend. Funny how we always desire more then we have.
This song was like an anthem - I was going to be like the kid in the song. It didn't happen quite as I imagined back then, but what in life happens just as we imagine. What I didn't realize at the time was that I was living that dream already.
This song is about the dreams we dream, and sometimes they can come true. :)