There can never be a true pleasure if discomfort is nonexistent. There's just now way to tell which is which if the other does not occur. 
This is the reason why success is much sweeter if it is hard-earned. 
Pleasure and pain can also be one of the most potent motivating factors in fact, without having to realize what is pain and pleasure there is no reason for anyone to really want to have their lives improve. 
Use pain to help you decide the things that you don't want and use pleasure to encourage you to want good things in life.
Our brain is so hardwired in the dichotomy of pain and pleasure so use it well to your advantage :)

Cheers!