Headaches are difficult to deal with. They can lead to canceled plans or a sick day from work because you cannot look at a computer screen or you simply cannot deal with bright lights and the regular chatter of co-workers. Back and Joint pain, meanwhile, can keep you out of commission for a long time.
They can require bed rest or therapy for the most significant situations. All of these conditions, however, can sometimes be traced back to a single vitamin deficiency.

First, the Truth about “Vitamin” D
Vitamin D is not a vitamin. Instead, it is more like a hormone. However, instead of being made by the thyroid, it is produced by the skin when it is in sunlight. It is needed for multiple processes within the body. Therefore, calling it a vitamin, which is optional, is not accurate.
Cortisol needs a sufficient amount of Vitamin D to be produced. Insufficient amounts of cortisol leads to pain and inflammation of the joints. This requires cortisone shots to alleviate the pain. Back pain is related to a lack of Vitamin D and also deficiencies in vitamin B12, B5 or B6 as well.
The Reasons for the Pain
Headaches can occur due to a lack of Vitamin D because people with a lack of Vitamin D do not sleep properly and suffer from depression. The lack of sleep, along with the pain associated with Vitamin D deficiency can contribute to headaches.
The issue with suffering from depression is that anti-depressants increase serotonin levels to deal with the depression, but they tend to increase the issues with insomnia because the serotonin levels remain higher, even at night when you should be sleeping.
Women who give birth tend to be the ones to suffer most from Vitamin D deficiency. They have their Vitamin D levels depleted by the baby, where it is required for development. Failing to get back out in the sun and rebuild those Vitamin D levels can mean poor sleep habits, can lead to postpartum depression and can mean mom and baby have sleep issues. This is not good for anyone.
What to Do
Now you know how serious it is to have Vitamin D, what can you do to rebuild your levels? The answer is get more time in the sun. It is that simple. It only takes about five minutes in the sun to start making a difference in your Vitamin D levels.
In order to appropriately rebuild levels that are severely depleted, spending two to four hours in the sun every day would be helpful. Since that is not something that can be easily accomplished, supplementing with 5,000-7,000 IU each day.
If you start supplementing and still have headaches, some magnesium might be a good idea as well. Sunflower seeds can be helpful to get more magnesium, or an investment in a supplement is a good way to go. Either way, this combination should help relieve the headache, joint and back pain you may be suffering.
Sources:
http://drgominak.com/vitamin-d-hormone.html
http://www.webmd.com/pain-management/features/vitamin-d-deficiency-and-chronic-pain-link
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3841620/