The investigators hypothesize that pregabalin will decrease post-operative pain scores and analgesic use following robot-assisted endoscopic thyroidectomy compared to placebo. The primary outcome will be acute postoperative pain, measured by a verbal numerical rating score (VNRS) and total analgesic consumption during postoperative 48 hours. The secondary outcome will be the incidence of chronic pain and hypoesthesia in the anterior chest at 3 months after operation.