Wherefore, must you?
Wherefore means why, not where. When Juliet says: "Romeo, Romeo! Wherefore art thou Romeo?" she is lamenting Romeo's name, referring to the feud between their two families. Why are you Romeo? The one man I'm forbidden to love?
This is wrong: Wherefore art thou, Romeo? and Juliet? on what would have happened had the couple lived.
And this: Wherefore art thou, Vaporware? seeking nominations for the killer apps that never were.
And this is just nonsensical: Shaista, Shaista, wherefore art thou? on a Pakistani couple who supposedly have troubles of Shakespearean proportions.
It's worth pointing out that if "the comma of direct address" is used, it's wrong. Juliet isn't addressing Romeo. It's a soliloquy. If you removed the address, it would simply be "Why are you?" and that is wrong.
More here at CJR's Language Corner.