Random Water Pressure changes

Seriously. One day about a month ago, the sprayer in the kitchen lost pressure. It barely works at all now. But right around the same time, the upstairs shower suddenly gained an enormous amount of pressure. I'm talking near bruising amount of torque. Interestingly enough. It's the only place with any good pressure at all. Other than the outside hose spickets. I'm confused to how that is, at all possible.