https://www.youtube.com/watch?v=RbKmMXrYJgA https://www.youtube.com/watch?v=AI12WA4uZOw

Здесь http://uk.forvo.com/word/шутка/#ru и здесь http://uk.forvo.com/word/щука/#ru

Hello, Ш is [sh] Щ" is pronounced like [sh] + [ch] or like [s] + [sh].

Of course yes. Check the link given above.

You have to listen a native language person to understand t the difference.