We need to do a clinical examination and fundus examination for correct diagnosis I suggest you consult a neurosurgeon at the earliest

There can be many reasons like migraine etc. One of the common reasons is computer vision syndrome. Blink frequently & Ensure that you take frequent breaks any look at least 20 feet away from computer screen time to time. Reduce staring at your smartphone if you use one. Ensure that you eat well and in time and drink enough water. Also get your bp checked. These are simple things to prevent your headache. If it is not relieved you will need a detailed consultation & evaluation to rule out other possibly dangerous causes of headache.