Emotions are a great way to control your dreams. Dream characters respond to emotion. Get angry, your DCs get angry and agitated. Confidence as an emotion is probably the most useful for control in any given situation. You don't need a switch, it's very easy to generate emotion, especially when you know the dream isn't real.

As for feeling pain, everything requires your attention to exist. You only feel what you focus your attention on. Again, no switch required, just be careful with your focused attention.