Clifford Law Offices is bolstering its medical-negligence practice by adding Kenneth C. Chessick and three associates with his firm. Chessick, a licensed physician who has also worked as a general surgeon, has run his own firm since 1984 and focused exclusively on representing plaintiffs in medical-malpractice cases. “By merging his practice into Clifford Law Offices, we’re able to give him a platform to continue his good work,” said Robert A. Clifford, the firm’s founding partner. &ldquo …