GOLD COAST, Australia (AP) — Olympic gold medalist Missy Franklin is being treated for a back problem, putting her in doubt for the Pan Pacific championships starting Thursday. Franklin, who won both the 100- and 200-meter backstroke at the 2012 Olympics among four gold medals, claimed six golds at the world championships last year, including a repeat of the 100-200 backstroke double that she won in London. Franklin is one of the American stars at the meet which include 18-time Olympic gold medalist Michael Phelps, who is four months out of retirement as he attempts to compete in his fifth Olympics at Rio de Janeiro in 2016.