i hardly ever have to use my pinky. easy pro tip: start your four fingers going red to orange, and use your index finger to go the other way to hit the green. much easier and less strain. practice makes perfect
And another thing.....instead of playing on easy, play on expert in practice mode on slowest and get used to the many many notes, and work your way up (if you have the time and patience). it'll all work out in the end. good luck.
Also i think i never mentioned this, but i have 19 years of real guitar under my belt.....lovin it!