In terms of headaches, I suspect the effectiveness of meditation as prevention/cure probably depends on the underlying cause behind the headache. For example, if you're prone to tension headaches, and through a Dhamma practice inclusive of meditation, you reduce the underlying tension, goodbye tension headaches.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine