Even though brains are in total control of pain, your brain also does a lot of that without you. For instance, brains modulate pain based on a number of other things that are completely out of your control, or rather difficult to control, or even just impractical to control. For instance, if you view a painful hand through a magnifying glass, it will actually get more swollen and inflamed — that is, if you make it look bigger, it will get bigger. And the reverse is true! (See Moseley et al.) Use optics to make it look smaller, and swelling will go down. Incredible, right? Jedi pain tricks!
But here’s the (large) catch: do you have a de-magnifying glass handy? Where do you buy even one of those, let alone a big one? What happens if the pain isn’t in a place that’s so easy to de-magnify, like your low back? Although dang interesting, the de-magnification trick is not generally a practical approach. The effect is real under the right circumstances, but trying to use it as a treatment is like trying to take a magician’s trick home with you. For more about pain and “mind over matter,” see Pain is Weird.