Your symptoms and high parathyroid hormone (PTH) level of 455 suggest hyperparathyroidism, which elevates calcium levels and commonly causes severe headaches. This is occurring alongside your hyperthyroidism. The definitive treatment for hyperparathyroidism is usually a highly successful, minor surgery to remove the affected parathyroid gland. For hyperthyroidism, medications like methimazole can help regulate your thyroid. I highly recommend consulting an endocrinologist. They will check your calcium levels and perform imaging (like an ultrasound) to tailor your treatment. Rest assured, these conditions are highly treatable, and correcting your hormone levels should resolve your headaches.