There are far too many things in life that are wrong that feel good and far too many things that cause pain that are right for this to function.
One could make the argument that if what you are doing minimizes future pain, then it cancels out the near term pain in the face of the long term, with the result being less pain.
While I would agree that minimizing suffering overall is an important piece of the puzzle, this one idea actually shows blatantly that the pain and suffering model is overly simplistic.
Pain does not define right and wrong. If I drive in both lanes, No one is in pain or because hurt but is wrong by the law. If I throw rocks onto my neighbors law, it doesn't cause pain, however it is wrong to do. Pain is a product of actions down in performing acts that are right or wrong but doesn't define it.
No, pain is not what genuinely defines right and wrong, because sometimes the right thing is not the most comfortable. Giving something up so that another person can have it is not comfortable, but it helps someone else. Sometimes, what is comfortable to you is something that hurts or kills someone else, but that does not make it right. Pain and justice are different things.