You might want to get your vitamin D levels checked. A new study from Finland found adults low on “D” were twice as likely to experience frequent head pain, compared to those with plenty of vitamin D. The reason? Because there are “D” receptors in the area of the brain linked to pain. And if there isn’t enough vitamin D available, the receptors may transmit pain signals from your stiff muscles, instead, triggering a headache. It’s tricky to get sufficient vitamin D from food and sunlight alone. But talk to your doctor before you start taking a supplement, to make sure it’s the right treatment for you.