It's a scientifically proven fact that your brain cannot determine the difference between reality and imagination. If you were to completely relax and measure your heart rate when it's at a nice relaxed place and then spend a few seconds thinking about a painful experience from your past you'll notice that your breathing gets shallow and your heart rate increases just as if you were experiencing that same event here in the present. The great thing is that this works for positive experiences as well.
We have barely tapped the awesome power of our resourceful brains.
Evolve on!
Its true, the mind can do so much more than what we are aware of as yet!
Untouched soil as yet!