My Scalp Has Had Some Hard Sores, Some Flaking, General

My scalp has had some hard sores, some flaking, general itching & a burning sensation on much of my scalp for 4 or 5 months. I've tried every medicated shampoo I can find. No improvement. I am ready to go to a doctor, fearing hair loss and also seeing that my usual home-remedy approach has failed. Age: Mid sixties, female. Height 5'7", weight always less than 140, take various vitamins but no prescribed medication, no known allergies, generally very good health. I use temporary hair color. I live in Arizona.