Yes, Pennsylvania workers' compensation insurance companies often use investigators. They are allowed to follow you, take photos, and talk to your neighbors.
In addition, we suggest you be very careful about anything you post on social media sites, regardless of your privacy settings. These networks are considered 'public domain,' which means insurance companies and judges may use the information against you.
If you are seriously injured and are following your doctor's orders regarding restricted activities, you should have nothing to worry about.