Vitamin D3 is obtained from the diet or from exposure to sunlight. Low levels of Vitamin D3 in the blood are quite common. Rarely this can cause deficient bone mineralization, known as osteomalacia and result in bone pain. Doctors can order vitamin tests, and home tests are also available. Vitamin D3 supplements are widely sold.
Osteomalacia is discussed on this web page, which advises: "To prevent deficiency, normal daily recommended intake for adults is 200 to 400 units. Most seniors require vitamin D supplementation of 400 to 1,000 units/day." Higher doses are given for some weeks to treat osteomalacia, but taking high doses for long periods can cause toxicity.
Several patients have reported that their coccyx pain was apparently caused by low levels of Vitamin D3:
Updated 2021-09-05