Physical Martyrdom

All of a sudden, out of no where, an almost unbearable pain in my very upper left shoulder / neck occured. I mean the pain is terrible, and it's really killing me. This is probably the worst pain imaginable, since I hardly can move my arm nor turn my head around.

Honestly, I really need to get rid of this pain, so any suggestion for a treatment is appreciated/wanted.

- a.s.a.p. -  please.