If you use GoToMyPC and use the same username and password on other sites, hackers may have stolen your log-in info from one of those other sites and been able to log into GoToMyPC. There's no apparent indication that GoToMyPC has been hacked directly.
You should get a mandatory password reset notice at GoToMyPC next time you log in. So log in now and change your password.
And stop using the same username and password on multiple sites. [;)]