Swelling of the neck may be related to thyroid disease, enlarged lymph nodes and so on. 1. Thyroid disease: Insufficient raw materials for thyroxine synthesis, such as iodine and other trace elements, will produce relatively too much thyroid stimulating hormone, so that the thyroid cells are overgrown, and swelling of the neck occurs. Common thyroid diseases include hypothyroidism and nodular goiter. 2. Enlarged lymph nodes: It is possible that the upper respiratory tract is infected by virus or bacteria, which spreads to the lymph nodes and then reacts and proliferates, possibly causing enlarged lymph nodes in the neck. It is usually accompanied by symptoms of upper respiratory tract infection, such as coughing and sputum. In addition to the above, swelling in the neck can be caused by other reasons. It is recommended to consult a doctor for further examination, to identify the cause with the help of the doctor, and to actively cooperate with the doctor in handling or treating the problem.