[rutledj]

I have a little confusion surrounding what notes I can play when I change chords. Let's say I'm going from Am to C.

So at first I'm playing the notes around the Am shape. When I go to C does that mean that any note in the C major shape is valid or do I still have to keep in mind that I'm in the key of Am. I've tried this and some of the notes in C just don't seem to fit. Just wondering if there is a rule around this.

Thanks
Rut