Photo by Bradley Meinz. This story appears in the February 2011 issue of Milwaukee Magazine. “Na na na.” Tinkering with that funny little phrase in a soundproof, nondescript brick building in Wauwatosa are the two members of the band Chester French, holed up in a tiny room, working on the melody for a song. The duo, a nationally known pop group with hip-hop influences, is big enough to be working anywhere in the country, but frontman and Milwaukee native D.A. Wallach is loyal to his hometown, though the city hasn’t exactly returned the feeling. In jeans, red high-top sneakers…