blurring of vision can be due to refractive errors of the eye.
it can be due to cataract
, or corneal oacity due to various conditions or due to any structural in the eye.
headache can be due to tension, migraine
pain at the back can be due to strain or long hours of work.
i would advise you to not be anxious,
have good rest and if the symptoms do not subside i would advise you to consult a physician.
i hope i have answered your query.