One very powerful and effective way to work with this tendency to push away pain and hold on to pleasure is the practice of tonglen.  In tonglen practice, when we see or feel suffering, we  breathe in with the notion of completely feeling it, accepting it, and owning it.

Without loving-kindness for ourselves, it is difficult, if not impossible, to genuinely feel it for others.

All the terrible things we do to ourselves and others from alcoholism to character assignation to abuse to murder come from one cause: the inability to stay present with an uncomfortable feeling in the body and seek short-term relief.

The painful thing is that when we buy into disapproval, we are practicing disapproval. When we buy into harshness, we are practicing harshness. The more we do it, the stronger these qualities become. How sad it is that we become so expert at causing harm to ourselves and others. The trick then is to practice gentleness and letting go. We can learn to meet whatever arises with curiosity and not make it such a big deal.

WE ALREADY HAVE everything we need. There is no need for self-improvement. All these trips that we lay on ourselves—the heavy-duty fearing that we’re bad and hoping that we’re good, the identities that we so dearly cling to, the rage, the jealousy and the addictions of all kinds—never touch our basic wealth. They are like clouds that temporarily block the sun. But all the time our warmth and brilliance are right here. This is who we really are. We are one blink of an eye away from being fully awake.

The way I regard those who hurt me today will affect how I experience the world in the future. In any encounter, we have a choice: we can strengthen our resentment or our understanding and empathy. We can widen the gap between ourselves and others or lessen it.

In tonglen practice, when we see or feel suffering, we  breathe in with the notion of completely feeling it, accepting it, and owning it. Then we breathe out, radiating compassion, lovingkindness, freshness - anything that encourages relaxation and openness.  So you're training in softening, rather than tightening, your heart. In this practice, it's not uncommon to find yourself blocked, because you come face to face with your own fear, resistance, or whatever your personal "stuckness" happens to be at that moment.