Delayed-onset muscle soreness, the sore and stiff muscles you experience 24-48 hours after exercise is not a good indicator of the effectiveness of your training. In fact, it can be argued the opposite way. Muscle soreness is an indicator of your inability to tolerate training.
Many people judge the effectiveness of their training session by how sore they are the next day. Again, this is partially erroneous. Delayed-onset muscle soreness is a by-product or side effect of strenuous exercise training, especially strength training. Most of the time we accept it- it comes with the territory. Train hard get sore. Eventully, you won't get as sore as your body adapts to the regular training.
In my experience, muscle soreness can accumulate with regular training and become counter-productive. Recovery is key. If recovery is not incorporated into your overall training plan, then symptoms of over-training can start showing up (decreased performance, chronic muscle stiffness and soreness, irritability, insomnia, elevated resting heart-rate, elevated or decreased appetite, and more).
Proper exercise programming is key to minimize muscle soreness or at least manage it so it does not impair your performance. It has taken me many years to appreciate this. So, if you are training consistently and feel like you are not recovering from your training, maybe we need to reevaluate your training program, adjust your intensity and volume, and make an effort to add more passive and active recovery in to it.
Remember, more is not always better. Smarter is better.