| Do a search, this one has been done a plenty!
But I'll say this... If you can't sing it then it probably will sound like mindless noodleing as a solo. The best solos are one's you can sing and play each note at the same time, because it will usually come from your soul more.
The main American scale is the Chromatic scale. So combine ideas from the Chromatic scale and your pentatonics while sticking around the chordal tones NOT the root notes. Most of what makes a great solo in music theory is arpeggios not scales.
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"If you don't feel it, don't play it." ---James Jamerson
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