Stomach pain half a year after thyroid cancer surgery may be related to malignant tumor recurrence and metastasis, chronic gastritis, gastric ulcer and other reasons. 1. Recurrence and metastasis of malignant tumor: if thyroid cancer recurs and metastasis occurs, it can cause malignant tumor in stomach and lead to stomach pain. 2. Chronic gastritis: the gastric mucosa can be damaged for a long time and repeatedly due to oral medicines and other factors, which can cause stomach pain. 3. Gastric ulcer: if stomach pain is more obvious after eating, accompanied by symptoms such as abdominal distension, nausea, vomiting, etc., gastric ulcer can be considered. It is suggested that those who have stomach pain half a year after nail cancer surgery should go to hospital for consultation in time, clarify the cause of the disease, and carry out standardized treatment under doctor’s guidance to avoid delaying the condition.