What is involved in getting a CT scan? Mri?

See your doc. First you have to see a doctor to be evaluated. If your symptoms suggest something that needs further work-up, then your doctor may order a ct or mri. Your insurance company may have to approve as well.
Lying still. If your doctor wants you to have a scan you will need an appointment. Mr and ct could require an IV contrast injection during the scan. Ct scans are rather quick(few minutes) . Mr requires about 20 minutes, possibly more. Once you are positioned you may instructed to hold your breathe for a few seconds. Other than IV injection there are no real sensations. Quite simple to have done actually.