Yes, if you have a Strict 'NAT' type then you will have trouble finding/joining games, and yes there is a solution. You will need to portforward some ports to give Black Ops II full access to the internet. The ports you need to portforward can be found all over the internet, and a good place to learn how to portforward is here: Free Help Forwarding Ports - PortForward.com
If you have any further questions or if this does not work then please add me on steam (waikatoboy)