I am in a job where I am in front of a computer for most of the day, and after I have been staring at the screen for so long, it can give me blurred vision and I have real trouble adjusting to the screen to the point of feeling dizzy and getting a headache. I also have this problem when reading particularly small writing. Should I be concerned? It is getting annoying, and I don't know whether glasses would help ease it a bit.
Given that you are having difficulties with concentrated near vision tasks such as computer and reading I feel it would be sensible for you to have a sight test with your local Optician. The Optician will be able to check your near vision and advise you if glasses would help. Computers do cause glare which can make the eyes uncomfortable, this can be reduced by an anti-reflection coating on your spectacles if you require them.