it sounds like the muscle you are talking about is called the SCM, or 'sternocleidomastoid' muscle. many massage therapists will stress its importance in headaches, and sometimes even sinus problems. it's definitely linked to TMJ symptoms. the eustachian tube is affected by this muscle and there are alot of lymphatic nodes in and around it, so if they were swollen, the muscle might seem larger.
usually there is tenderness when glands swell. antibiotics will only help if there is a bacterial infection... it amazes me how many times i have read (just today) that "my doctor gave me antibiotics" without reading about symptoms that indicate a bacterial infection. it almost looks like some doctors do it to get people out of their offices...
no offense intended to those responsible MDs out there!
i've had tinnitus, clicking, popping, roaring and hearing loss in my right ear. mechanicall speaking, it always seems worse when my neck muscles are tight.
anyone with tightness in this muscle and plugged ears, consider having a massage with a licensed therapist, with focus on your head, neck and shoulders. let me know if you find any relief... and good luck.