If there are no seated jobs, but you can't stand for prolonged periods, the employer would seem to be able to require you to use a wheelchair or some other way to avoid excessive standing--or they could even potentially fire you, since while an employer must make "reasonable accomodations" for disability, an employer is not required to employ someone who cannot do the job for which he or she was hired.The above is a general answer: in a case like this, the specifics are critical to determining your rights. You should review the specifics of your case with an employment law attorney or contact your state's equal/civil rights agency for guidance. Good luck.