If that is your current routine in your signature, I would guess the flaking is probably build up from cones, and this can also coat your scalp and let bacteria grow. Shea Moisture shampoo doesn't have the ingredients to take cones out either. I would switch to a low poo that contains coco betaine and cocamidopropyl betaine. If you want to use a no poo exclusively, I would suggest getting rid of the cones.
I wouldn't suggest a baking soda scrub, this can very easily damage the hair and make it dry, unless followed by an acidic rinse to close the cuticle.
2c-3a - med width- low porosity - high density - growing out to donate
POOS: Sevi Seabuckthorn, Neutrogena Anti-Residue
RO/LI: Suave Coconut / KCKT
PT: CNPF, gelatine mix
COLOR: henna, amla & indigo
= humectants in low dews