During the sequences
You lie on a sliding table. For many exams a coil, which looks like a plastic frame, rests over the part being scanned. The radiographer leaves the room but talks to you through a speaker and can hear you. Ear protection or headphones are routine.
The machine knocks, buzzes and sometimes pauses. Those pauses are normal. You should not feel pain from the magnet. A few people feel warmth. If contrast is used, the injection feels like a blood test, sometimes with a brief cold sensation.
The hard part for some people
The hard part is staying still in a partly enclosed space, not pain. If that worries you, say so before the day. Wide-bore scanners, music and, in some clinics, light sedation are easier to arrange in advance than in the changing room.