What to Do with Pain in Neck, Dizziness, and Click Sounds in Jaw with Braces On?

The symptoms you describe are commonly associated when an improper bite is affecting the temporomandibular jaw joint (TMJ) and the related facial muscles.  An orthodontist who understands occlusion and TMJ will check for these symptoms throughout treatment.  As the teeth shift, so does the occlusion - or how the teeth come together when you bite down.  Even a very slight change may trigger some of these symptoms.  Hopefully by the time your ortho treatment is complete, the bite will be in a stable, comfortable and functional position and all symptoms will subside.  Keep your orthodontist posted, though, as you realize these symptoms, especially if they worsen. 
 

The body is adapting to the new positions of the teeth, and often these issues are temporary.  Give it some time and most of the time everything resolves.  If not, seek an office with experience with TMJ treatment.  A simple "night guard" is often not a long term answer.