In my right eye, there is continuous strain coming from the top side i think from the very top of the eye socket. it is very stressful to look at a computer or mobile screen. difficult to look up. is this related to the eye or sinus?

Although there are several ocular issues that can feel like "eye strain" such as inflammation (uveitis) and ciliary body muscle strain from focusing (accommodation), what you're describing seems more likely to be extra-ocular. I would suggest an evaluation with an ophthalmologist to rule out an ocular cause and then to see an ENT to check out the sinuses that surround the orbit.