Thyroid problems are usually one of 3 types. 1. The gland makes too much thyroid hormone, 2. The gland makes too little thyroid hormone, and 3. Cancer develops in the thyroid gland. All of these can cause the thyroid gland to enlarge. There are very few thyroid gland problems that are inherited from a parent to a child. In addition, only in extreme circumstances does the thyroid enlarge enough that the neck appears to swell.
Most of the time when the thyroid gland enlarges it is not noticeable except by a physician who is examining the thyroid gland. The thyroid gland sits just below the Adam's apple. In general, it cannot be seen unless you are feeling for it under the skin. If someone has a very thin neck, and the gland is quite large, it may be visible. Otherwise the swelling in your neck is most likely caused by something else.
I suggest that you schedule an appointment with your primary care physician
. He or she can examine your neck closely and determine what is causing this swelling. This may include getting a CAT scan done of your neck. If your doctor
is concerned that you have a thyroid issue, then you may have thyroid function tests done.