Marshfield resident Laurel Egan Kenny has been named chief operating officer of the Quincy-based South Shore Chamber of Commerce. Kenny, a former president of the Marshfield Chamber of Commerce, is the founder and principal of a marketing, communications, and training company called Turningpoint Communications, which serves financial services companies.  She is vice president of the Treasury Management Association of New England. Kenny started work at the South Shore chamber in August, according to vice president John Stobierski. Her responsibilities include managing the organization’s growth and its services to members.