Soloing over power chords riffs...HELP!!!

HI!
I play electric guitar from three years..
I can play scales very fast...but i have many problem playing the solos...
I would ask to you how i can search some scales to make instead of the solos in the songs...
for example: I could play the rythmic part of the metallica's song " motorbreath" but i can't make the solo.I heard that the solos of the metallica album "kill'em all" are only some pentatonic scales..but how i can found that scale?
In motorbreath during the solo the rythmic guitar make this riff:
D--6----------------6--6----------------6-----
A--4--4-4-4-4-4-4-4-4--4--4-4-4-4-4-4-4-4--6-6
E------------------------------------------4-4
I consider this powerchords as C# and G# major chords..
I search a scale that fits in this 2 chords and i found a large list of scales as:C#maj,C#maj bebop,c#dominant bebop,C phrigian,Ebem Dorian..and lots more,but none pentatonic.
My questions are:
How i can consider powerchords?(like normal major chords?)
To solo i can simply make one of the scales that i found..but wath's the best to use?
How i can use a pentatonic scale over a lot of powerchords?
And definitely..How i can find scales that fits over riffs composed by a lot of powerchords?
Please answer me!!
I hope that my questions are clear..
Bye and thanks!!

Power chords are neither major or minor. Power chords, also called 5th chords, contain no third, so, therefore, there is no minor or major tonality.

This means that virtually any scale based on the root of the power chord can be used to solo over that particular chord. Over just a C power chord, you could play C major, minor, dorian, phrygian, etc, and it would all sound fine. Once again, this is because the power chord contains no 3rd.

However, if you're attempting to solo over a progression of power chords, it's the sequence of the chords and their relative positions that determines what scale to play.

I don't know what the other chords in the progression are, but for just C# and G#, you could play almost anything. Any scale that contains all the notes of the G# and C# power chords would work. I would start out in G# minor pentatonic.

WHAT ARE YOU WANTING TO SAY ? THE EMOTION OF PATTERN?
UMM THERE IS SO MUCH YOU CAN DO....BY A TRIAD ( THREE NOTES MAKE A TRIAD )..CHORD....THAT IS WHERE YOU FIND THE EXACT MODE FOR THE SONG OR KEY....YOUR ONLY USING PERFECT 5THS
( POWER CHORDS )..THE PATTERN IS SO SIMPLE..--I WOULD PLAY G# IONIAN OVER THIS METALLICA SONG..........
AS FAR AS WHERE OR HOW TO PLAY A PENTATONIC SCALE OVER CHORDS----FIRST OF ALL.. IS IT MAJ OR MINOR?..PENTATONIC ISNT JUST MAJ...THERE IS A MIN PENTATONIC..FLATTERN THE 3RDS TO MAKE IT MINOR.. ANY METALLICA SONG IS NORMALY IN
E PHYGIAN...I FOUND THAT TO BE A VERY COMMON PATTERN OVER ANY OF THERE SONGS..ALSO LOOK AT THE ROOT NOTE PATTERNS TO PICK THE MODE..THEN DECIDE THE MODE OF THE SEVEN IN THE PROPER KEY THAT FITS WHAT YOU ARE TRYING TO SAY....ADD THAT 3 RD NOTE TO THE POWER CHORD EMBELLISH IT A LITTLE...IT WILL GIVE YOU MORE ROOM TO PLAY & PHRASE....HOPE THIS HELPS YOU OUT ....GOOD LUCK