You might think me naive, but I really did believe (without being aware I did), that everybody who experienced these painful emotions actively worked toward resolving them. I discovered that was not the case. I actually found out that people held on to those emotions as if they were a permanent thing.
In other words if I hate someone, I just keep hating them.
If I am resentful about a situation, I just stay resentful.
If I am bitter about a life condition, I just keep being bitter.
If I feel envious of someone, I just persist in being envious. And so it goes with various painful emotions.
Many people seem to believe that they have to stay in their painful emotions. This is not true.
All emotions can be evolved to higher consciousness. In fact, the purpose of emotions is the Creator's way of pushing you to be a more divine you.
You don't have to stay in your painful emotions forever. You can choose to heal. Or, more accurately, you can choose to expand your consciousness.
The reason you would want to evolve is because holding on to painful feelings is hugely destructive on every level of your being in every way. When those painful feelings have stayed with you a long time, they end up expressing themselves in your body through illness. However, you don't need to let that happen. You can always choose to heal.
Any time there is something uncomfortable in you, examine it. See what needs to change. If you're resentful, explore why this is so. Then seek a way to dissolve the resentment. There are many good books out there and there are many therapists and many healing modalities that can help. Choose whatever resonates with you most.
Remember, you do not need to live with a painful feeling forever. You can heal. Choose to heal.