I have tachycardia and hypertension. no doctors know why. ecg and ultrasound came back normal apart from heart beating too quick. no family history.

Eval secondary cause: You are quite young for hypertension (htn). If they have not yet done so, i would definitely think about eval for secondary caues for htn- some include an adrenal gland tumor making too much hormone- Epinephrine (pheochromocytoma), cortisol (cushing's syndrome), aldosterone. Also high thyroid, high parathyroid, or medications/ supplements. Fast hr- can be normal or could be due to above causes.