muscle spasm
"An absolutely excruciating sharp pain in my shoulder woke me up..so severe I cried for my wife to take me to the ER at 3am.  Turned out to be a pinched nerve in the neck sending pain to the shoulder.  A prescription for Metaxalone was given that I got filled along with Naproxen.  

The Metaxalone works very well for me.  I split the pills into two halves and use when it feels like the shoulder pain will flare up.

No "loopyness" or drowsiness.  I am a 24 year recovering alcoholic and this medication works well."