This may be a ganglion or soft benign cyst ..... I have copied something on research .. A lipoma, a smooth, rubbery, dome-shaped lump that is easily movable under the skin.
A cyst, a sac of fluid and debris that sometimes hurts.
Cystic lesions from acne are large pimples that occur deep under the skin.
Branchial cleft cysts are found in the neck and do not usually cause problems unless they become infected. These cysts are most common in teenagers.
An epidermal cyst (also called a sebaceous cyst) often appears on the scalp, ears, face, or back.
A ganglion is a soft, rubbery lump (a type of cyst) on the front or back of the wrist.
A thyroid nodule, which is an abnormal growth on the thyroid gland, or an enlarged thyroid gland (goiter) in the neck just below the Adam's apple. Tonsillitis may also cause swelling in the neck.
A salivary gland problem, such as inflammation, a salivary stone, an infection, or a tumor.
An inflammation of fatty tissue under the skin (erythema nodosum) or overgrown scar tissue (keloid). It does sound like a benign lump from your description, all the same have it checked out ....