Loud. The MRI makes a noise like a jack hammer. It doesn't hurt at all, you will feel nothing. You should just close your eyes, think pleasant thoughts, and try to hold as still as possible so that the images are as good as they can be. There's no need to fear at all. I've had an MRI and it's really easy.
Check out. Radiologyinfo. Org.
No worries. It takes about 30-45 minutes to do. Good luck.
Yes, an ENT can order a head MRI.