Bill Curry, 65, raises cattle on the same land in rural Oklahoma once owned by his father and generations before him. Each quarter, for several years, he has made the 2½-hour drive to Oklahoma City for an epidural in his spine to treat his back pain. But this year, because of a new Medicare program, Curry has traveled a little more often. In February, during one trip, he was told unexpectedly that he needed preapproval for the procedure. Then he went again a month or so later to get the