PackTrackPlus is an adware program that displays pop-up ads and unwanted advertisements not originating from the sites you are browsing, so I'm not quite sure what you mean by it has access to this site?
Also, it's very likely that PackTrackPlus was installed on your computer while you were installing some other software that you'd downloaded from the Internet. Whenever you install software be very careful because quite often other software that they don't tell you about can come bundled with it. The best way to find out if that's the case is to always choose a custom install if that option is available. A custom install should show you every piece of software that could be installed on your computer during an installation and give you the option to opt out of installing software you don't actually want.
As for removing it from Chrome, you might try looking here:
How to remove PackTrackPlus adware [Virus removal guide]Scroll down to the section that comes after Windows and that has the headline "Remove PackTrackPlus from Google Chrome".