I'm going to avoid my grandmother
Is there a reason you want to avoid your grandmother?
The pain in my chest when I look at her is unbearable
I'm sorry you are feeling that way. I hope you can talk to her about what you are feelings since grandparents aren't around very long.
I feel like she's going to die soon. I should avoid her just to deal with it.
There are some situations that can only be dealt with via avoidance. If your grandmother is upsetting you so much that it is hurting you, just be polite when you are forced to be around her and otherwise, keep avoiding her. Putting your feelings first is okay in these situations.