Hi, Yes, deficiency of active vitamin D can cause muscle cramping. Based on the history you seem to have developed symptoms suggestive of hypoparathyroidism (abnormally low levels of parathyroid hormone) resulting in decreased serum calcium levels apparently caused by surgical removal of parathyroid glands along with thyroid gland. Whereas parathyroid hormone is required for the activation of vitamin D in the kidneys. Once activated vitamin D is required for the calcium absorption from the intestines as well as from the kidneys. So, due to lack of parathyroid hormone makes blood calcium levels fall (hypocalcemia) and blood phosphorus levels rise (hyperphosphatemia), which can cause a wide range of symptoms, including muscle cramps, pain and twitching. You should start taking vitamin D and calcium supplements (calcium carbonate) to restore your blood calcium to these levels. They usually have to be taken for life. I also advice you to take a high calcium and a low phosphorous diet. Calcium is found in milk and other dairy products, green leafy vegetables, nuts, poultry, fish and fortified flour and bread. You will also need to have regular blood tests to monitor your parathyroid hormone, calcium and phosphorus levels. Hope I have answered your queries. Let me know if I can assist you further. Take care Regards, Dr. Mohammed Taher Ali