Isn't it great when something helps. Glad for you.
I have read that in order for your muscles to relax or to have the energy to move our cells must have the right amount of magnesium and calcium in them. If either mineral is missing the other mineral will just hangout in the cell waiting for the other one to show up. Once it does, the cell releases the created energy or relaxation depending on the bodies request/demand.
Magnesium and calcium need each other in order to be metabolized. I think you said you are on a calcium supplement already. If you have too much magnesium in the body the body will leach calcium out of the bones to metabolize the magnesium. I wonder if it would work to muscle test yourself to see if your getting enough calcium. It changes sometimes how much you need, especially if you start taking magnesium.
I take magnesium and calcium at bedtime to sleep. I recently gave it to my elderly mom, who has been unable to sleep more than 5 hours a night for years. She is now sleeping 8 hours and wishing she had been willing to try it years ago.