A 19 year old female presents with pain in the neck for 5 days. She is not able to wear tie for her job because of neck pain. H/O fatigue and lethargy for 10 days. She had flu like symptoms 20 days ago which resolved spontaneously. BP 110/80 mmHg, Pulse 48/min. Extremities are cold and dry. Neck is very tender. ECG normal. TSH is elevated. ESR 30 mm/hr. Next appropriate step