Am I doing something wrong or not regarding of my workout routine?

There is a saying "No pain no gain" right? Is that always true or not necessary according to people who do know and have experience in the business.

I had always heard or known that in order for your muscles not to get sore days after your training, you have to stretch after you work out, that is what I had always heard and known for years.

But then there are time when you do work out even if you stretch minutes after your work out is done, the following days your muscles are sore, which for many will think, indeed that person did work out hard

What happens then if a person works out and stretch but their muscles never ever are sore the following days, Does that mean the workout was not worth it then?

Also I had heard thatn when a person had a long time of not working out the muscles are rusty and when they work out again, it is almost 90% possible their muscles will get sore following days as the body was not used to a certain type of exercise so the body part is resented, like doing a new exercise for the first time.

I dont know in my case if Im doing something wrong or not. I kinda of work out when I do the exercise in the moment Im doign the workout I feel sore when lets say I do certain muscles, legs or abs, etc but I feel the muscle in the precise moment of the exercise. But then when it comes the following days, not one once of my muscle is sore at all.

Is this normal or not?

Am I doing something wrong or not regarding of my workout routine?
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