Mayor Thomas M. Menino broke a toe on his left foot and will be forced to wear a protective boot for several weeks, his spokesman said. Menino did not fall or drop anything on his toe, but had an aching left foot. He went to the doctor earlier this week, according to the spokesman, John Guilfoil. “The mayor had noticed some pain in his left foot recently,’’ Guilfoil said. “He had it checked out, and they found a broken toe.’’