The "sternocleidomastoid muscles" are most likely those which are giving you radiating pain from ear down to neck/shoulder/arm(Google for picture of this muscle if unfamiliar with its location). There are two of these muscles in the superficial layers of the anterior (front) portion of the neck that make the shape of a “V”, and they are primarily helpful in rotation, flexing and extension of the head. They run from the center of the sternum (breastbone) and the clavicle (collarbone) up to the mastoid process, a bone in the skull located behind the ears (close to the inner ear). These muscles tend to spasm "bunch up" and become sore/painful when left in this state (yes, it can occur on just one side and progress down the shoulder and in some cases all the way to the fingers). Press under the corner of your jaw (by your ear) to feel if it is unusually tender. When these muscles spasm it can cause strong ear pain just as you describe Try this next time it starts to hurt: use a massage vibrator from behind the ear, to down under the jaw, working your way to where the clavicle meets the base of the neck next to the esophagus. If you are in a place where you cannot do that use your thumb and first finger to grab and massage the muscle from the jaw down to the front of the neck. Remember to search for a picture of this muscle on the internet to see what you are looking for.
I hope this helps.
I have same from 3 months