Kevin, you can take the chorus anywhere you want it to go melodically; you can even change the key in the chorus. The thing is, in the end, typically by the last two lines, you have to seque smoothly back into the verse chord structure.

I don't love the key of C, but in the examples you gave, try going to Em, F, Cadd9, G... which would take you back to your verse chord of C. Experiment. Play an A2 on the 5th fret - sounds similar to an Em, yet adds a little something. Become a chord junkie. I don't know of any literature that can point you in the right direction here; I wish I did. Just have fun with it, and make sure that by the end of your chorus, you take the melody and chords back home.

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