What could cause hyperthyroidism if it's not graves, hasmitos, pituitary problem? i have low tsh 0.01 but normal free t3 (liothyronine) and t4 and normal total t3t4

Already answered: Hi. I already told you: hyper-functioning ("hot") thyroid nodule is most likely, but a phase of subacute thyroiditis (ST) is certainly a possibility. Following thyroid function over time, or a 123-I thyroid scan (and uptakes) would tell the difference. This all assumes you're not surreptitiously TAKING thyroid hormone (which would look like ST, but unlike ST would have a suppressed thyroglobulin).