1) Herniated/degenerated disc in neck
2) Cervical spondylosis; bone spurs in the neck vertebrae pressing on the nerves.
Following investigations would be required;
1) X-ray of the neck spine
2) MRI of the neck
3) Nerve conduction velocity (NCV) study
4) Electromyography (EMG)
Physical therapy, neck traction, deep electrotherapy are the recommended treatment.
Headache and pressure behind the eyes can be due to what we term as cervicogenic headache. This headache is caused by referred pain from the upper neck (cervical) joints. The headache is caused by neck movement or sustained awkward head positioning. So people who work long hours on computers are liable to have this kind of headache. Migraine and tension-type headache can be the other possibility for all of your symptoms. Physical therapy is the preferred initial treatment for cervicogenic headache.
If your symptoms are moderate to severe; these should be evaluated by a doctor; so you may consider going to the hospital. Investigation would be able to clinch the diagnosis with a physical exam by the doctor. Your symptoms are unlikely to be due to mini stroke (termed as transient ischemic attack / TIA) or other serious cause, still getting an evaluation is recommended as these have going on for some time.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.