3. Can you expand your erogenous zones? If so, how?

Definitely. That’s because, as noted above, your brain mediates the whole erotic stimulus/arousal process. And there’s one thing anthropology, history, and our own experience teaches us. Any part of the human body can be a sexual part, either as giver or receiver of pleasure.
How you figure out how you like to be touched? The answer is similar to that given to the young violinist who stopped a New Yorker and asked how to get to the Carnegie hall: “Practice”.
In this case practice includes masturbating, occasionally touching yourself in new ways or in new places. Be adventurous with your partner as well. Ask for new things, try new things and invite your partner to do the same.
Pay attention to how the new stimuli feel; don’t just assume that you know-feel them. Breathe deeply, open your senses, and appreciate texture, pressure, sensuality. Look, really look at your body being touched or kissed. Listen to what it sounds like, and smell what it smells like.
You can also play with the meaning of these new touches. You “know” that having your hair stroked in intimate, perhaps sexy. You know this because you learned it, not because it’s intrinsically sexy. What about having your body’s less familiar corners and treasures caressed and licked? Can they “mean” sexy, intimate, playful, daring, sensuous?
To expand your horizons, use babies as role models. They aren’t aware of having sexual and nonsexual parts; as a result, their entire bodies, and every touch, are sensual and sexual. Conceptualizing a distinction between sexual and nonsexual body parts is what starts a baby on the dubious road to “civilization.”
In all of this, a flexible, nonjudgmental attitude is the key. Watching or criticizing yourself will make experimentation less comfortable. Play with your sexuality. Enjoy what you discover, and discard what doesn’t appeal to you.