Is it supposed to hurt when you wash out your tooth extraction with salt water? i was told one glass of water with one tablespoon table salt

Rarely-unless: After an extraction, the necessary gentle rinsing with warm salt water, to remove any debris that gets caught during eating, should not produce pain. If it does there is a chance that the bone within the socket has become inflamed and produced a dry socket. If it continues and you notice a bad taste and bad breath, see your dentist to evaluate and help you treat it.