ServerAlias may be a solution for you. It is the more effective apache config method than rewrite rules. Your domain become faster if you do not use rewrite engine.
Code:
<VirtualHost *>
ServerName www.shop.com
ServerAlias *.shop.com
#ServerAlias anotherdomain.com #optional
#ServerAlias www.anotherexample.net # optional
# and more config
</VirtualHost>