First of all get a CT scan brain (plain) along with cervical spine
screening to rule out any intracranial injury as well as cervical spine injury
The commonest injury following head injury
is intracranial haematoma but it usually follows high impact injuries and is associated with symptoms of altered sensorium, headache, vomiting or seizure at the time of impact.
Have you been noticing any episodes of blurring of vision?
Now as you are having episodic headace along with neck pain
get the scan done.
The nasal bleed as you have noticed that the blood looks very thinned out, (next time you can just check if on your handkerchief there is a clear halo around the blood) you need to rule out any leakage of cerebrospinal fluid
(clear fluid) and yes that comes from further up the nostril as you have mentioned. What happens is at times there is some cribriform plate fracture.
Are you a known hypertensive?
Anyways dont worry it is curable.
As mentioned a plain CT scan brain can diagnose or rule out all the facts