How can I force a business owner to remove my name from their public sign, i stopped working there over 4 mo ago, sign remains displaying my name?

You would first have to speak to the owner of the business and request your name to be taken off the sign. If you have exhausted those options you may file a law suit under privacy laws, specifically under the tort of appropriation. Appropriation is the unauthorized use of one's name or likeness for defendant's commercial advantage. The public must know that use is identifying you specifically, but this requirement is met if the business is using your name. If you have exhausted your other options and feel this is the next step, you should consult local counsel to determine proper filing procedures.