The repetition of a word or phrase is very popular in song lyrics because of its inherent musicality. In the Katy Perry song, Firework, she repeats the phrase, ‘do you ever feel‘ in the first two stanzas:
Do you ever feel like a plastic bag
Drifting through the wind, wanting to start again?
Do you ever feel, feel so paper thin
Like a house of cards, one blow from caving in?
Do you ever feel already buried deep six feet under?
Screams but no one seems to hear a thing
Do you know that there’s still a chance for you
‘Cause there’s a spark in you?
The repetition of the phrase followed by a negative image has a cumulative effect: you feel bad, you feel bad, you feel bad, you feel bad. So, when the anaphoric line changes to ‘do you ever know’, we are clued in that a change is coming in the song, and sure enough it becomes more upbeat, and the stanzas that follow offer consolation. In short, the balm the song offers makes more sense because of its initial focus on the ailment: lack of self-esteem, isolation, loneliness.