Straight On by Heart Chords
“Straight On” by Heart uses something music theorists call modal interchange. This is where you combine chords from different keys that revolve around the same tonic.
Basic Straight On guitar chords here.
Bm A G are vi V IV from the key of D, which is also the key of B minor or B Aeolian mode.
Bm E are ii V from the key of A, which is B Dorian mode.
Bm Dsus2 are also B natural minor or B Aeolian mode.
Bm F# stem from the B harmonic minor scale. This is where you take a B natural minor scale (Aeolian mode) and raise its 7th in order to create a dominant V chord.
Notice that each of these keys centers on a Bm chord. They are parallel scales rooted on the same tonic. You can use B minor pentatonic the whole time. Or you can switch scales, B minor scale, B Dorian and B harmonic minor (you only play harmonic over the F#).
Key changes, modal interchange and the harmonic minor scale are covered in my Fretboard Theory guitar theory program.