I have been having a moderate pain in my neck around the back of my ear down to just behind upper jaw for 6 days. no fever. just on my left side.

Pain behind ear : Your pain could be related to a tooth infection or a problem with your temperomandibular joint (tmj). You'll need to see a dentist to carefully examine that area, and take xrays to check for an infection.

See a dentist.: Among the myriad of things this can be, TMJ problems are included. If a physician can't locate a problem, go see a dentist trained in treating TMJ problems for an evaluation.