Some quiestions?

[Toxcatl]

DMC ( Playmaker SA ) 90%
MC 122%
MC 107%

I should train pass go and shoot with them only ?

I believe, all midfielders matter, DMx and AMx included. Or maybe all the players with white Passing skill (everyone except pure defenders and GK). Or maybe all players matter. I'm not sure, so if someone can confirm or refute this, it would be great.
You have fairly low Passing tbh, I think that's the reason.

There're several drills that train Passing, efficiency of them is different (because different players have different set of white and grey skills). What's good for training Passing for AMx isn't good for DMx. MC and MR/L probably need different drills too. If you want the best result, you have to train your players individually.
You can download ITP (link in my signature) and experiment with different schedules for different players to understand what's better. If you need help with it, I'm here to answer any questions.