If your answer is yes to all of the above questions, you might have vitamin D deficiency. The normal level of vitamin D is 20-50ng/ml. To confirm this deficiency ask your doctor to give you a blood test on vitamin D or you can go to a lab where you can check your vitamin D level without any doctor's reference. I have severe deficiency of vitamin D and I am taking vitamin D supplement as per my doctor's advice. I was suffering for back pain. I was not able to sit for a long time. My back would pain a lot if I would do so. After having my blood work done my doctor confirmed me that I have severe deficiency of vitamin D. Then he advised me to take 4000IU daily. If you feel that you might have this deficiency do not take supplements on your own, first check your blood then consult with your doctor and only then you should take supplements. After taking vitamin D supplement I feel better now. I take vitamin D3. To keep our body healthy we need all the vitamins and minerals. So try to be more careful about your diet. If you have a poor diet you may catch up with many deficiencies.