I feel your pain. I recently went to the doctor for ongoing ear infection/ear problems and she prescribed me some steroid stuff for both ear and scalp as she concluded that my scalp had mild exzema. Prior to this I had been (mis)managing my itchy/flaky/dandruffy scalp for years. Maybe you have this?
I swear by Body Shop's ginger shampoo (they've just brought out the conditioner too!).
My problem was as soon as I'd blow dried my hair after washing there were inch wide patches of flakes lifting off my scalp. It was grim! I tried extra rinsing, not 'scrubbing' my scalp, a special shower hair brush for massaging, T-gel, SLS-free... you name it I tried it, but nothing worked.
Someone on here recommended the ginger shampoo and it fixed it within two washes. You can get a 100ml bottle for £2 to try it out so not much lost if it doesn't work for you.
I tried moisturising (coconut oil etc), a natural-bristle brush, sls-free shampoo and shampooing less but the only thing that helped was apple cider vinegar. My hairdresser said I should stop using shampoo entirely and use acv instead but I don't buy into the nonsense that acv is a miracle cure for everything and I hate the smell so it was a hard sell for me. About 10 days after my haircut my scalp was still clear so I'm (grudgingly) still doing it. After massaging it into my scalp I leave it on for a while (sometimes I mix it with aloe vera gel first so it isn't so runny), rinse it off and put some conditioner on.