Hopefully your son has an account of his own on this machine and is not using the one that you use.

I am assuming that you can go to other websites, just not secure ones. Is that correct?

Is the OS X firewall turned on ? If yes, turn it off.
Have you installed any 3rd party firewall or security software lately?
Or uninstalled any?
Create a new account on that computer and log onto it. Still got the same problem?

That should keep you busy for a while