I have a swishing in my carotid artery, had an ultrasound everything was clear is it possible that i just hear the blood flow but everything is fine?

Venous hum?: A true carotid bruit is dangerous but if you actually had this from a narrowed carotid, it would have shown up. Three foolers are (1) a tight aortic valve with the murmur transmitted; (2) some other heart murmur, perhaps from athletics; (3) a venous hum, not in the carotid at all, but from turbulence in the internal jugular or subclavian vein or where they join. Have a few more docs listen.

Yes: May be bruit noise from a branch and not dangerous if you have had testing.