According to Stewart B. Leavitt, MA, PhD, editor of Pain Treatment Topics and author of the report, "our examination of the research, which included 22 clinical investigations of patients with pain, found that those with chronic back pain almost always had inadequate levels of vitamin D. When sufficient vitamin D supplementation was provided, their pain either vanished or was at least helped to a significant extent."
I would recommend 2,000-4,000 units of vitamin D a day. I would also consider a supplement that supports healthy bones and that has high levels of vitamin D, and also other nutrients that could help relax your back muscles and decrease pain from back arthritis.
Jacob Teitelbaum, M.D. is one of the world's leading integrative medical authorities on fibromyalgia and chronic fatigue. He is the lead author of eight research studies on their effective treatments, and has published numerous health & wellness books, including the bestseller on fibromyalgia From Fatigued to Fantastic! and The Fatigue and Fibromyalgia Solution. Dr. Teitelbaum is one of the most frequently quoted fibromyalgia experts in the world and appears often as a guest on news and talk shows nationwide including Good Morning America, The Dr. Oz Show, Oprah & Friends, CNN, and Fox News Health.