Matchmaking Issues? Try This:

If you have trouble finding match or if match making is generally slow, please check if you network connection is using the correct NAT Type. We recommend our users to use NAT Type 2. Players who are on NAT Type 3 will have issue in matchmaking and friend invites. This is due to the restriction of your router on the PS Network. 

Here are some instruction on how to change the NAT Type:

http://www.playstationing.com/ps4/how-to-change-your-nat-type-on-ps4-and-ps3/839