I've been searching how Spell Resistance work for days and I haven't found an answer. What is the roll to pass the target's SR? I mean the DC would be the SR, but what do I add to my roll?
From the Pathfinder SRD section defining Spell Resistance:
To affect a creature that has spell resistance, a spellcaster must make a caster level check (1d20 + caster level) at least equal to the creature's spell resistance.
So the bonus to the roll is your caster level.