Chest tiredness in the morning while taking medication for hyperthyroidism is often not due to the medication; it may be an indication that the hyperthyroidism is not under control, and the amount of medication taken may need to be adjusted or other methods of treatment such as through radioiodine therapy or surgery may be considered. Patients with hyperthyroidism usually need to take medications such as propylthiouracil, methimazole, and propranolol, which do not cause symptoms of chest tiredness. Therefore, patients with hyperthyroidism who experience morning chest tiredness while taking medication need to consider the possibility of uncontrolled hyperthyroidism. Uncontrolled hyperthyroidism may lead to various cardiac arrhythmias such as tachycardia, and therefore, the patient may feel the symptoms of morning chest tiredness. Patients with hyperthyroidism who experience symptoms of morning chest tiredness while on medication may need to have their medication adjusted, or may consider other methods of treatment such as radioiodine therapy or surgery. If this symptom occurs, seek medical attention and do not increase or decrease the dosage of your medication on your own.