So in the physical aspect of the sense, I do believe that with no pain there is no gain. Especially if you want to see results sooner. Sure, people can lose 50 pounds over a year or two year span and you know what, you hardly recognize it. However, if you work your ass off and train and push through all of the temptations and pain of physical change, then yes the more pain the more gain.
In other aspects of life, they always say that someone who achieves success has experienced many and many a failure. It’s the perseverance to push through the difficult times and all of the failures to actually see something take shape and form. Whether it be an idea, an experiment, a new design, you have to reach stopping points and you have to break through them.
So with pain, you also gain. You do not just lose but you also gain such things as strength, perseverance, dedication, and motivation. You want to see results, you have to make an effort to see them and do something to positively strive towards your outcome.
The more pain, the more you gain.