Is flaking scars from decades old sunburns something to worry about my upper back and shoulders are covered in small round scars resulting from multiple severe sunburns in my early childhood. They periodically burn and itch and will flake and scratch off

I . I would recommend you get evaluated. These could possibly be actinic keratoses (see picture at link below), which are precancerous scaly areas that are typically seen on sun damaged areas. They can be treated with liquid nitrogen if that is the case. Regardless, probably a good idea for you to see a dermatologist given your history of sunburns.