Survivor guilt and existential pain - why womb twin survivors hurt so much

I read this article today on existential pain.

"Existential pain" is a widely used but ill-defined concept. Therefore the aim of this study was to let hospital chaplains (n=173), physicians in palliative care (n=115), and pain specialists (n=113) respond to the question: "How would you define the concept existential pain?" A combined qualitative and quantitative content analysis of the answers was conducted. In many cases, existential pain was described as suffering with no clear connection to physical pain.

From this article it seems that the pain some people suffer that is related to simply being alive. I wonder if they are the womb twin survivors?  This kind of pain is an excruciating expression of survivor guilt and is very common among womb twin survivors.  The only way to express this kind of pain is to hurt yourself, punish yourself and let others punish or bully you: also to magnify any kind of personal slight or physical pain out of all proportion.

The healing is to forgive yourself for the sin of being the one who lived. It's that simple.