stop, prevent, defeated, dejected
沮 centers on obstruction and its emotional result: stopping or preventing action, and the dejected or defeated feeling that follows being blocked.
沮 combines 氵 (water) with 且, which likely contributes the sound. The idea of water being dammed or blocked may connect to the meanings of stopping and dejection.
Water 氵 meets a barrier 且, like a dam that stops the flow. When progress is blocked, you feel defeated and dejected.
For ソ, imagine a dam so solid that it stops the water with a soft 'so' sound: so -> ソ, and the water is prevented from flowing.
check; obstruction; hindrance; impediment