Reading glasses work fine when the screen is very close to your face such as a laptop screen. However if it's a separate monitor that's ~30 inches away, reading glasses are slightly blurry which can lead to eyestrain and headaches.
https://www.warbyparker.com/learn/wp-content/uploads/2023/04...
Look into it if you suspect it's a contributor to headaches: https://www.google.com/search?q=computer+glasses+%22intermed...