It is a widely used concept currently without standard definition.
In many cases, existential pain has been described as suffering with no clear connection to physical pain. But the concept of “existential pain” is controversial, because different groups define it differently.

The following information is the result of a study using the question: “How would you define the concept existential pain?”
- Chaplains defined it exclusively as existential suffering, with an emphasis on existential guilt and unresolved religious questions.
- Palliative physicians stressed more often existential pain as being related to extinction and impending separation; they focused on issues of meaning and death anxiety, which can amplify the suffering from pain and definitely reduces quality of life regardless of whether physical pain is present.
- Pain specialists emphasized that living is painful, with never-ending suffering, particularly in patients with chronic pain.

In summary, existential pain is mostly used as a metaphor for suffering, but also is seen as a clinically important factor that may reinforce existing physical pain, or may even be the primary cause of pain, in agreement with the current definition of somatic symptom and related disorders.

See reference for more information.

Adapted from Strana P et al. Existential pain—an entity, a provocation, or a challenge? Internet. Accessed on July 5, 2018. Available at https://www.jpsmjournal.com/article/S0885-3924(03)00516-5/fulltext