Go over ALL your medications with your pharmacist, the prescribing doctor, other doctors, and google it yourself with the word "toxicity" and see what you learn. I had similar symptoms and it turned out to be a too high dose of medication for atrial fibrillation. Good luck
It might sound a silly question but have you had a full ophthalmic assessment by a consultant opthalmologist? They should use eye drops and various eye scans. I had similar symptoms to you on one side and they went on for years. Not all the symptoms were the same as yours though. I saw GPs and optometrists as I was suffering from headaches, eye pain, facial pain, even tooth pain on affected side. Eventually a hospital consultant diagnosed Corneal Epithelial Basement Membrane Dystrophy. This was causing recurrent corneal erosions and constant foreign-body sensation and pain in my eye which radiated all over my face/head on that side. I think I also had migraine which was complicating the symptoms and causing after-images. I had a procedure under local anaesthetic on my left eye called alcohol delamination which resolved the problem wonderfully. The condition can recur apparently, as there is a genetic component, but I am happy for now. Worth investigating, if nothing else. It seems to be hard for doctors to spot. Good luck! I know how awful head and eye pain is
Have you found an aswer ?
Also look up "macular pucker"