''Self-massage.'' This is the answer that singer Mya gives during a chat about her work in EA's new videogame James Bond 007: Everything or Nothing. For the record: We were inquiring how this videogame enthusiast sought relief from the repetitive stresses of game sessions. (She says a squeeze between the thumb and forefinger does the trick.) Drawing upon her experience in the studio (the most underrated member of the ''Lady Marmalade'' quartet has released three CDs -- two platinum, one gold) and on a movie set (she played a jailbird in Chicago), Mya did double duty on the Bond game. In addition to some voice acting, she also cowrote and recorded the game's title song. While she may not be a 007 scholar (she had never heard of George Lazenby), Mya definitely has gaming cred: ''I've played videogames in the bathtub,'' she boasts.