if you are noticing positive results from your exercises, then your workouts are going fine in my opinion. muscle soreness may or may not occur. I am a bodybuilder who has trained for 14 months now and I don't usually get sore. Yesterday i added deadlifts to my regimen and today I know for sure exactly which muscles are used in the lift because my legs and upper back are pretty sore. But I noticed with other lifts, such as the bench press, that it is very difficult to get sore unless I include a single repetition set at or near my maximum lift. perhaps you are already well adapted to your regimen. your trainer seems to want you to give your absolute maximal effort, but for me, this only occurs when I add a new exercise or when I give a maximal single rep effort as when I go to break one of my own lifting records. usually I do an exercise for 3 sets of about 8 reps and I don't get sore from this, though over the last 14 months, I have made appreciable gains in both strength and mass. and remember, everyone's physiology is different. your trainers are only interested in the best results for you. what you are happy with should take top priority in my opinion though.