Is this noodle thing I feel on one side of my neck a middle cervical sympathetic ganglion nerve? About 0.3 cm wide 0.8 cm long. FEELS like tendon.

Unlikely, but... This is unlikely to be related to the cervical sympathetic ganglion, unless you have a Schwannoma or other unusual situation. If you are concerned that there is something going on please see a physician for evaluation.