@bickypeg i concur with Apricot re the flashes. I've had episodes for years and a few times they were the vitreous tears - large "floaters" - that just seem to settle themselves. Other times they were what's called "migraine without the pain" and is a benign condition that feels scary when it comes on if you don't know about it. And it's not a visual issue per se, but vascular. Can be brought on by meds, or red wine, cheeses, coffee, caffeine, dark chocolate - yeast foods. Symptoms start with the kaleidoscopic zig zag flashes in one eye only. If you don't take a baby aspirin at the onset you can have appx a half hour of visual disturbances - sometimes that eye doesn't see part of the field of vision, it's goes to grey. First few times scared me so much I almost passed out thinking I was going blind, but later learned you can stop it all with a baby aspirin. It has been years now since I've had one. I'm glad the symptoms haven't returned for you.
As for sleeping, I found a small memory foam pillow for the neck ...used under the knee ...really helped provide comfort to me! I kept experimenting with all of the 42 pillows I now have in the bed to see what worked best where. Trial and error. Then when I could bend the knee enough, I found back sleeping with knees bent relieved lower back pain as well as a propped up neck and head. Work those pillows!!