I had severe muscle and joint pain, not spasms, but as Johnny said, the magnesium really helped with with muscle pain as it did with the anxiety that I had.
Threelac (probiotics) also helped with my muscle pain.
I had been diagnosed with Rheumatoid Arthritis and found out through Iridology, that my weakness was in my connective tissues. The Iridologist recommended the amino acids L-Lysine and L-Proline. The combination of these two amino acids has really helped too.