Extreme dry scalp and hair. Solution.

I've dry ,frizzy ,unmanageable hair but no issues with scalp before. But from one year scalp also getting too much dry and dry hair problem got worsen also too much hair fall and thinning . White substance falling when even lightly scratching and combing ,I don't know whether it is dandruff or dry scalp problem. I regularly apply oil (sesame oil ) and using chemical free shampoo and conditioner ,even though hair and scalp drying and also leads to split ends. Recently started applying neem oil. I want to grow my hair from childhood but not happening ..Iam so tired of doing because no results and worsening problem.Iam 26 years old (woman). Please help ,it would be so helpful !!hope you will give me better solution ..Thanks in advance .