There are many causes for dizziness and balance disorders, including life-threatening conditions. The CT and MRI scans you had were to rule out more serious causes for vertigo. They are not meant to find out exactly what is happening. When the scans come back clear, your primary care physician may try medications that are available and see what happens.
However, the vestibular/balance system is very complex and sometimes the cause is neither sinister nor straight forward. An example is Persistent Postural-Perceptual Dizziness (PPPD).
In less straight-forward cases, specialized professionals and/or diagnostic testing may be needed to lead you to understanding what is causing your dizziness and to implement appropriate management strategies.
The road to diagnosis and management of a dizziness and balance disorder is often a journey and we understand that it can be confusing and frustrating.