Vitamin D deficiency causes a defect in the ability of the body to deposit calcium into the collagen jello-like matrix in the bone. As a result, the covering on the bone which contains pain sensing nerves is easily deformed resulting in throbbing aching bone pain. Patients with osteomalacia often complain of achiness in their muscles and bones. These non-specific aches and pains in the bones and muscles are often misdiagnoses as fibromyalgia or chronic fatigue syndrome. There have been several studies demonstrating that patients with severe bone and muscle pain and muscle weakness associated with osteomalacia have dramatic improvement in their symptoms when vitamin D deficiency is corrected. It takes months to years to develop osteomalacia and associated symptoms and it takes three to six months before significant improvement in symptoms results from correcting vitamin D deficiency.
Holick, M.F. Vitamin D deficiency: What a Pain it is. Mayo Clin. Proc. 2003; 78(12): 1457-1459.
Malabanan AO, Turner AK, Holick MF. Severe generalized bone pain and osteoporosis in a premenopausal black female: effect of vitamin D replacement. J Clin Densitometr . 1998;1:201-204.