I suspect that it's not dry scalp at all but product build up, especially when looking at the things that you've described using.
Have you been doing any clarifying washes between this? If not, then I can almost guarantee what you're describing is product build up.
Also, using oils and your scalp is NOT NECESSARY as your scalp produces sebum naturally. When you do hot oil treatments and the like you should NOT apply it to your scalp, but to the hair.
Wash your hair with diluted shampoo and a couple tablespoons of baking soda. Scrub your scalp clean. Follow with diluted Apple Cider Vinegar (I say about a quarter cup of ACV to about a shampoo bottle's worth of water). DO NOT RINSE. Apply conditioner, let it set, THEN rinse out the conditioner and ACV. You can't do a baking soda wash w/o ACV b/c they need to balance each other out. Also the ACV before the conditioner opens your cuticle for the conditioner to really penetrate.
Do this at least once a month but no more than twice. I guarantee your scalp problems will be solved.
For god's sake do NOT put shea butter or anything like that on your scalp. That's just asking for flare up and even more build up/scalp issues. smh"