I've had a couple. Proton alignment is an imperceptible state. You're experiencing more significant neurological changes reading this message than having your protons reoriented.
My wife works on MRI sequencing and has pretty long (> 1 hour) MRI scans quite often (2/3 times a week) as they all test each others research on themselves. She mentioned there are some scans where you actually do feel them and it's quite uncomfortable.