Thanks for writing your query.
Headaches in your case can be due to cervical spondylosis
. When you are reading or studying you have your neck in down position. This can result in increase in headache.
Also get your blood pressure, recorded as blurring or black spots when you stand up quickly from kneel down position can be due to sudden decrease in blood pressure, a condition known as Postural Hypotension
Following investigations will be helpful :-
1. X-Ray cervical spine
AP and Lateral view
Also get your eyes tested for Refraction
by an Opthalmologist and get yourself fully examined by a Physician.
I hope this is helpful to you.