Karin did a good job answering this question.
The key to success and continuing to see improvements in physique, specifically, is muscle confusion. That’s just my opinion, but as a general rule your body will eventually get used to a certain training modality, and it may not respond as well (you won’t be sore and you won’t lose ability, but you won’t see any improvement either). It’s always good to change it up. Keep it interesting. Keep it fun. As long as you’re having fun doing different and challenging physical activities, you’ll be happy AND fit!
Don’t overdo it. Don’t be a victim of overtraining syndrome. Think of your body like a bucket with a hole in the bottom. Think of exercise recovery like water in the bucket. You put exercise in, and you have to recover. The rate at which the water leaks out of the bucket can be thought of as the time it takes to recover from a bout of exercise. If you keep putting water in the bucket (you exercise too often without proper rest and recovery), then the bucket will overflow and your body won’t respond to any training because it can’t keep up. Make sense?
The soreness (when you get sore) should be just that, soreness. NOT PAIN. You can minimize delayed onset muscle soreness by doing a proper warm up, stretching before exercise, and doing a proper cool down and stretching after exercise. In my book, a good stretch is one that puts a welcome amount of “stretch” in the muscles you’ve worked out. The stretch should be held for a good 10-15 seconds. Repeat that stretch at least once, and stretch for all areas that you worked out. Stretching your warm body (you got your blood flowing before the stretching, never stretch a cold muscle) for just 10 minutes per day can lead to permanent tissue elongation, which is generally a good thing because it can decrease the risk of injury when exercising.
In the future, when and if you change your routine and start to get sore again, consider myofascial release with a foam roller or something simliar. It’s usually used as therapy for certain ailments, but athletes have been known to use it as well. Karin can tell you all about this. She knows things that I know not of!
Hope that helps a little. Karin was on the money with her answer.