Are you having any sinus pressure, pain or discharge?
What part of the head is affected by your headaches? Do they come and go? Are they generally worse in the AM or PM?
The normal CT is reassuring. However, it would not show a cause such as migraines, which are extremely common and often involve the vertex and temples. They may come on or months at a time, can involve nausea and other neurological symptoms that resemble a stroke.
The normal neuro exam is reassuring. :-)
Migraines are a spectrum disorder. Many are so mild they do not come to medical attention.
They can be hormonal
Have you had basic blood tests and hormone levels checked?
Increased intracranial pressure in the brain typically results in what is called "papilledema"which can be seen on examination of the retina and fundus.
Whoever examined your eyes should have looked . If they missed it, it still should have been seen on the retinal pictures.
Happy to help. Thanks question and support. Follow up anytime.