I too have found caffeine to be helpful with muscle aches and spasms. I thought it was just my body reacting in the "crazy" ways it seems it always does.

I also have sceptics when I drink a cup of coffee to be able to sleep.  This seems to relax my body enough most of the time to be able to make sleep possiable when nothing else will.

I too have have migraines and was advised against caffeine for this reason. i thought it strange since many of the migraines meds contain caffeine.

As the original post commented , I do not say this will help for everyone nor do I advocate it.  i am just speaking from personal experience from someone who also has trouble moving.