POP/ROCK Rick Springfield: ''View From Oz.'' (RCA Records 4660.) Rick Springfield has been labeled an artist for the teen-age listener, and probably quite correctly. Why? He writes fast, danceable songs about love and broken hearts. These songs, though, all tend to sound the same. And his appearances on a soap opera have only increased his pop-romantic image. But now there are signs he is trying to break away from past musical limitations with his latest LP. Although the result is a somewhat more diverse album, there's a problem - the chord structures are all so similar. Though this effort has some clever pieces and the capable hit tune ''An affair of the heart,'' it does not push Springfield past his previous limited appeal. Springfield has succeeded, perhaps, in slightly broadening his musical horizons - his song ''Tiger by the Tail'' has a tangible reggae influence, while the cut ''Me & Johnny'' has the flavor of a Bruce Springsteen song about nights in the streets - but his progress has been minor. There are still the sappy love songs, such as ''Soul'' and ''I Can't Stop Hurting You,'' which all sound alike.