Dear friend, welcome to HCM!
A normal CT scan
rules out significant brain injury
Headache , nausea can occur with subtle concussion
(blunt) injury to the brain which settles down in few days.
But pain in the neck and toward the arm may point to a spinal injury
Please see your doctor and get xray cervical spine
AP and lateral views to look for any injury there.
Sometimes an MRI is needed.
Can take simple OTC pain killers and anti-nausea medications till then.
Any deterioration in consciousness calls for an urgent visit to the doctor.
Take care and please keep me informed of your progress.
I hope to have answered your query satisfactorily.