Playing to a key

Hi i was wondering if i wrote a chord progression in the key of example. AMaj how do i work out what scales, Arps ect would go with it?

Depending on the progression you might use major scale, some of it's modes (mixolydian or lydian come to mind), pentatonic major or blues scale. These are mainly the ones I play with, so don't be restricted. Use two or more in one solo to get the contrasts and learn to use them to induce moods.