Magnesium malate is great for helping decrease pain and increase energy. It is magnesium with malic acid. I use the Source Naturals Magnesium Malate 1250 mg tablets, which are very inexpensive. I take 3 or 4 of these a day. i am not suggesting that people get many tests done, I just provided this link as a source of general information.

http://www.greatplainslaboratory.com/home/eng/fibromyalgia.asp
http://www.ihealthdirectory.com/malic-acid/

My theory about why you feel weird when taking calcium or magnesium supplements is that you are probably deficient in them. Do you take zinc supplements? when I am feeling horrible I usually get some relief from detox teas. My favorite is the triple Leaf Detox Tea. These teas have herbs such as red clover, dandelion, ginger, burdock, licorice root, and cinnamon which are very helpful in detoxification. Most of these herbs also have a diuretic effect.