What Causes Shooting Pain In Neck, Shoulder And Upper Back?

Three weeks ago, I woke up with a shooting neck, shoulder, upper back, and deltoid pain (basically the upper left quadrant of my body). I ve gone to a chiropractor and had several massages. The pain is subdued, but I am still experiencing muscle weakness when using my left arm. Trying to lift any weight strait out to my side is impossible. I have to keep my arm close to my side in order to lift it. I also have experienced fairly continuous slight nausea.