You can appoint a qualified individual to represent you in doing business with the Social Security Administration (SSA). The decision is a personal one and depends on your individual circumstances. Many attorneys and advocates who specialize in disability claims provide a free initial consultation.
Enlisting the help of a representative can improve your chances of winning if SSA denies your initial claim and you have to appeal. Many representatives accept payment on a contingency-fee basis whereby payment depends on a successful outcome. You'll find more information in the Social Security publication "Your Right to Representation."