No pain no gain. If you’re not sore after a workout it wasn’t a good work out.
Not the case!
DOMS (delayed onset muscle soreness) can happen when you embark on a new exercise regime / change your exercises / or vary the duration or intensity of your workout.
If you don’t ache whereas you did previously, this is a good sign. It shows that you have got stronger and fitter. Your body has built up and adapted to the training load you have placed upon it.
Are you lifting more weights / performing more reps / lifting the same weight with more ease / taking shorter rests? If the answer is yes, then you’re progressing. You don’t need DOMS to tell you that. DOMS are neither a good thing or a bad thing and should not be worn as a badge of honour as a sign of a better workout.