What It Is or What Is It?

i need to know who sing this song but the only thing that i heard was what it is or what is it i am not to sure of the worlds but i do know that it is a rock song

Try "I Don't Know What It Is" by Rusfus Wainwright

Does the song also go like:
You want it all but you can't have it
You want it all but you can't grab it
It's 80's or 90's.