Dan Weissmann kicked off his podcast last year by likening health care costs to water, arguing that Americans (the fish in this metaphor) are so surrounded by it that we can’t see how it changes everyone’s lives in very real, very painful ways. So each episode of “An Arm and a Leg” sets out to show you the water, examining a different person’s battle to pay for the care they need. Weissmann’s charming, empathetic and occasionally expletive-laden approach makes for an entertaining but sobering bottom line: Our health care system is broken, and everyone is suffering for it. Season 3 opens with Stephanie Wittels-Wachs — the sister of Harris Wittels and the creator of “Last Day,” the new podcast that begins with his death. But her episode isn’t about addiction or opioids. This is about the battle she pursued to convince the Texas state legislature to cover her daughter’s hearing aids.