Leah, this is just Jan being Jan, and not wearing my editor hat or any of the other hats I wear here. Yes, I think that some people's brains are more wired for coming up with creative ideas. I'll give you a musical analogy, since I know that you're a musician.
For a while, my little church had two pianists--a fellow named Bob, and me. Bob could read music a little bit, but when it was his week to play, we got lots of improvisation; the melody line in the treble, chords in the bass, fun little variations and riffs and arpeggios. When it was my turn to play, we got what was written in the song book, with maybe a brave little arpeggio at the very end.
I frequently told Bob, "I wish I could improvise like you--I'm so tied to the score." And Bob would reply, "I wish I could read music like you--I couldn't play that offertory if my life depended on it."
Bob and I have different musical gifts, but in the end, we're both capable of making music for the Lord.
So while you may not be gifted with an overabundance of ideas, you can still write. If you just have one idea, write about that one. If that just doesn't seem creative enough, use some "cheats" to get more ideas:
1. Get the Barnstormer app--hundreds of thousands of ideas
2. Ask for this for Christmas: http://store.mentalfloss.com/Storymatic#axzz2nH5b62mu
3. Or this: http://boardgames.about.com/gi/o.htm?zi ... Index.html
4. Find your own random prompts by placing your finger on a word in a nearby book, and then a second word in another book.
5. Text a friend or two, and ask them for a noun or an adjective. Write.
You get the idea. If your brain won't give you prompts, get them externally!