Hello,kindly have to evaluate whether it is headache or migraine and more over ,sitting in the same position prolong time might cause (cervical spondylitis)decrease your blood flow to brain might cause dizziness ,do you have any neck pain and blurring vision ,do you use spectacles for refractive error (eye problem) if so kindly check your power again ,increase in power of your vision might also cause headache persistently.
Next Steps
kindly get consult with these without getting further evaluation ,taking analgesic medication for headache is not good .
Health Tips
can do lifestyle modification ,if you sit for 20-30 mins just walk for 5-10 mins ,change your sitting posture frequently.
just move your head in all directions and rotate them , mobilization of neck can prevent cervical spondylitis.
hydrate yourself drink plenty of water , dehydration might cause dizziness and headache too.