TSH high (15) free T4 high (4.2) but free T3 low (2.1). 41 yrs old, has partial thyroid removal at 14. Hashimoto. Been on 300 mg of generic synthroid for 20 years. What does this mean?

Thyroid or pituitary. Not clear since both TSH and free T-4 are high. No data on T-4 Hashimoto can effect the thyroid tests either over acive and underactive and synthroid can effect them and raise them. Was thyroid removed because there was a tumor or was it overactive or underactive. A visit to an endocrinologist is in your future.