Vertigo on neck movement in old people is due to vertebral artery compression in neck. MRI angiography (MRA) is needed for that. Xray is of no use.
While in young adults or adults it is mostly due to BPPV. It is confirmed by Dix hallpike test done by doctors, MRI can not diagnose it.
Next Steps
get dix hallpike and epleys maneuver from ENT
Health Tips
if the dizziness persists at a time for long say more than 2 minutes and u don't have hearing problem then should visit Neurologist.