This is unusual, though there may be a couple of things to consider! Ultimately dryness signifies that the hair needs more moisture or is potentially being dried out in some way!  - Are these sections of your hair exposed to the sun more? For example, when you tie your hair up, are these sections more vulnerable to sun damage?  -Could the dryness be exacerbated by friction? For example, do you sleep on your side at night, causing your hair to rub against the pillow? Do you use a silk pillowcase? Do you wear a protective sleep style? -Are these parts of your hair coming into contact with any products that the rest of your hair does not experience? For example, skin care? Do you use a face spray/ product that gets onto the sides of your hair? Maybe this product contains ingredients that cause dryness, like fragrance, or phenoxyethanol? -Do you use any heat tools on these sections of hair, and not the rest? Do you use heat protectant? -You also mention that the hair feels stiff, which can be a sign of protein overload. Are you using any protein filled ingredients on these sections of your hair?