KIM RICHEY On her latest effort, the acclaimed singer-songwriter highlights harmonies    Kim Richey has been on the move—Colorado, Boston, Washington, South America, Europe and London, where she spent three years. She returned to Nashville for the third time last summer to make her new album, Thorn in My Heart. Richey’s first venture to Music City after college included a stint as a cook at the famed Bluebird Café where she glimpsed singer-songwriters...