Interesting indeed, Lizzie. Shingles without the rash is called Zoster sine herpete. Unfortunately, it does happen and is difficult to diagnose. That distinctive Shingles rash is usually the confirming symptom. You have my deepest sympathies on the post herpetic neuralgia (PHN), which I have also. Mine has lasted 4.5 years and counting. I take Amitriptyline and Gabapentin for pain control, which probably accounts for why my headaches have always been "manageable". My Docs have been able to make the association between dizziness or disequilibrium issues and abnormal intracranial pressure. It seems that the zoster virus messed up my body's ability to get rid of the spent CSF. Possibly some of the outflow holes are goobered up. The docs don't know the exact mechanics, but it seems that is the most logical explanation, or I may have had a touch of meningitis. The zoster virus is one nasty little bug. It has left me with nasty dizziness that prevents me from being able to work (I used to drive truck long haul).
When we overdo, it can easily bring out the left over symptoms of zoster, especially the post viral fatigue (PVF). It seems to be nature's way of reminding us that we need to take care of ourselves. I still find there are days when I have to do little as possible. Just keep in mind, we never get rid of the zoster virus. It merely goes dormant. Given the opportunity, like when our immune system has been weakened, it can pop out again!!