Childhood neglect and abuse, whether physical or psychological, confers a lifetime vulnerability to stress, anxiety, and mood problems. Such early-life stress is also suspected to contribute to the development of chronic pain in adulthood. In fact, there is growing concern that chronic pain syndromes may be a complication of posttraumatic stress disorder (PTSD). However, this link is particularly challenging to study because many stressful events that produce PTSD also produce physical trauma.

Source: Hypersensitivity to pain produced by early life stress worsened by later stress exposure