Your greyhound is distressed. Why do you continue to do something that obviously distresses him? Secondly, yelling no at him isn't very helpful and outdated type of training. If you want him to learn, positive reinforcement is the way to teach him, e.g. redirect and praise him for the wanted behaviours. There are lots of resources for positive reinforcement. Patricia McConnell's books are a good start and I highly recommend you read something asap. Honestly, we're only trying to help, and can't understand why you are not taking any advice for the benefit of your new greyhound. We're a passionate bunch when it comes to greyhound welfare, and we only want what's best for your greyhound.