Thyroid cancer is a common type of malignant tumor in the head and neck region. In its early stages, thyroid cancer has little effect on the body, and generally does not cause any discomfort. However, as the disease progresses and the tumor invades outward and metastasizes to distant areas, it can lead to various uncomfortable sensations. For example, if thyroid cancer invades surrounding tissues and organs, such as the recurrent laryngeal nerve, the patient may experience symptoms like a hoarse voice and choking while drinking. If thyroid cancer metastasizes to the cervical lymph nodes, the patient may also develop Horner's syndrome, which is characterized by a constricted pupil, drooping eyelid, and absence of sweating on the affected side of the face. If the patient develops superior vena cava syndrome, it can lead to difficulty breathing, chest pain, and swelling of the face and neck. If thyroid cancer metastasizes to the lungs or other distant areas, the patient may also experience chest pain, difficulty breathing, and coughing.