@divinityrose- many of your description sound like a tight SCM muscle that has trigger points. The Steronocleidomastoid muscle connects to the clavicle and up behind the ear but also controls a lot of movement and stability of the head. This tightness can cause a lot of problems and uncomfortable symptoms all throughout the head and neck. You will not feel it at the places it originating from. But most are the tightness just below the skull which sends off nerve response into the occipital and and trigeminal area. Neurologist will only locate the spot you show them. They won’t take the time to help you understand where it’s coming from. I would check, not with western medicine and look more into myofascial release. The part you mentioned under your chin is a muscle that gets very tight/reactive with stress, vision stress, and txting. Look to a physical therapist for postural assessment and musculature imbalance.