Why is the hot water pressure in your kitchen sink low but the cold water pressure is normal and as of last night both were equal and the hot water shut off valve under the sink does not shut off?

Answer 1

If the shut off valve turns but does not shut the water off, the washer in it has split and probably made it to the faucet. It was blocking part of the hole on the hot side and at some point either shifted or made it through the faucet and in in the screen in the end of the spout. Shut the main water off and replace the washer in the shut off valve.