Spam text messages

[manamaga]

Recently I have been getting spam text messages. There is no number, just 'New Message'. Is there a way that I can dig into the deep files of my phone and find the origin of these texts? It's a Galaxy S5 running Lollipop. I'm a network manager so I'm IT savvy but not really been too involved with android file systems. Any help / advice would be very much appreciated.