Hey guys, I'm trying to write my 1st song, which will be an instrumental, guitar based song. It starts off with the chord progression Am Gm Dm , which is in the key of D Minor. I want to play a solo/lead over these chords but I'm confused about whether I should only use the D Minor scale/minor pentatonic over the whole progression, or play to the chord changes (like use Am scale over Am chord and when it switches to Gm, switch to the Gm scale, etc..) ?? Thanks !
play the d minor scale but try to start on the chord note each time.

Just play whatever sounds good.
I don't believe it matters what scale you use