Hypothyroidism Support Group
Hypothyroidism is the disease state caused by insufficient production of thyrohormone by the thyroid gland. There are several distinct causes for chronic hypothyroidism, the most common being Hashimoto's thyroiditis and hypothyroidism following radioiodine therapy for hyperthyroidism. Advanced hypothyroidism may cause severe complications, the most serious one of which is...
A visit to your doc might be in order but I would not feel terribly urgent unless you really can't swallow and it swells up so you can see it when your head is NOT back.
I do know mine will feel tender and swell when I am having a flare up of my Hashi's and that sometimes it will swell up for other reasons like a case of thyroiditis, or even if the glands in the area are swollen from a virus or sinus issues. Also, to ease your mind a bit, bear in mind that about 60% of people get a goiter on their thyroid at some point in their lives and it just goes away.