0.25 is homeopathic management, typically, opticians, with their limited knowledge, when they cannot find cause, for your complaint,  prescribe such insignicant power as treatment. I suppose you see a local to doctor and get through examination. Hypertension to be ruled out for example. Sinus allergies or infections is another to be excluded. For young persons,  misuse of gadgets,  like mobile, tab is the usual cause of such vague complaints. Stop use of gadgets as a first step (use mobile as a communication tool) not as entertainment tool.

Get a dilated refraction by an eye specialist  to rule out any number . 0.25 usually  doesn't  cause headaches.  Second reason may be migraine. And for immediate  relief take a pain killer and see the doctor as soon as you can.