The pull chain on my ceiling fan that controls the on/off and speed pulled out of the socket. Is there any way to reinsert the chain or must I replace the switch; Is replacing the switch a DIY project?

You must replace the switch. It can be done if you follow the instructions, here they are:

Ceiling fan pull chain replacement and repair - Ceiling Fans N More (http://www.ceiling-fans-n-more.com/ceiling-fan-pullchain-replacement-and-repair.php)