Originally Posted by: Neal Walter

The scale you would play over any three chords would depend on what key the chords are in and if it's major or minor. Major is the 'happy' sounding key and minor is the 'darker/moody' sounding key.

But how do you find out the key?

Is there a relationship to the chords played, to the key it is in? Example; if I played g,c d. What key or what scale do I play a lead or riff to it?

Thanks for the great replies, Neil and Chris. Nice to get some help when needed and even better when you get more than expected. :)