Here is an list of video links to learn more about how we can use our brains to heal our minds and bodies. I've rematching a bunch of them. Though many illnesses are not "just in your head", the brain is a powerful tool for change and awareness and, if concentrated enough, there are some things we can use the brain to change!
Norman Doidge on the brain and neuroplasticity - YouTube
Annie Hopper on Dynamic Neural Retraining (She claims ALL healing can be done in the mind and she minimizes physical and nutritional based therapies. I don't agree completely but I support her work. The DNR method is unconventional and seems flippant or hokey at first but it is based on solid science including self-hypnosis and it does work. )