One step that should have been taken when your cocker was a puppy is socialization in all aspects of the word. Socializing in different atmospheres, people, dogs, distractions, noises, etc. What you need to do is bring him around new things, as tz1 stated, and slowly introduce him to them positively. When he responds in a good manner, reward him endlessly. The more he interacts in new situations, the less reactive he will be.

Scolding him or putting him in his crate can have adverse effects.

Scolding him - don't yell at him for a behavior. While you are yelling, you are reinforcing the behavior. Good or bad response from you does not steer the dog away from the behavior, it directs them how to respond.

Crating - if you are yelling at him to get in his crate, you are ruining his crate for him. He will begin to see it as a punishment versus a nice place to go when you're away or what have you.