eye strain and headache

my vision was perfect before the pandemic but due to a screentime it got worse but still it was -0.25, 0.75 but i never wore glasses.

3 years later when i started having headache i checked again, it was -1.75 in both eyes, after started wearing them recently, im having eystrain and even dr eyes when i look at the screen and more eye strain if i take them off with headache.

sorry for bad english, what's the problem and please how can i cure this.