What does dizziness, nausea and neck pain after a fall suggest?
No reason for concern
I read your question carefully and I understand your concern.
However you will be happy to know there is nothing in your history to suggest a brain lesion. Symptoms to suggest that would be confusion, behavior changes, weakness of the limbs on one side, seizures, double vision, progressively increasing headache and vomiting. Luckily you have no such symptoms.
Furthermore brain complications happen in the first 24 hours usually, beyond that they happen mostly in the elderly or those with other conditions affecting coagulation.
You should be so eager to have futile CTs which give some radiation. It is a small quantity admittedly but still enough to make unnecessary exams not recommended.
For the pain over the counter acetaminophen or ibuprofen can be used.
I hope to have been of help.
I am glad that you feel less worried now.
Regarding the pain, some local pain where you took the hit is normal due to damage to soft tissue (outside the skull, under the skin, not related to the brain). Another possible cause, a hit on the head is often associated with abrupt accompanying movement of the neck with some stretching and tearing of the neck ligaments and muscles which can leave some neck and headache till they gradually naturally heal. A 3rd factor is stress and anxiety after the hit which is often associated with tension in the head and neck muscles, tension which itself leads to pain.
Of course it can also be a combination of the three abovementioned factors.
As for the timing, as I said it is in theory possible but rare after the first 24 hours. Even those rare cases have been found both by literature as from personal experience in people aged over 60 or suffering from a previous disorder of coagulation such as hemophylia or treatment with anticoagulant.