Trauma is stored as activated neural circuits involving the brain and body, particularly the insula.

“to be clear traumas can't actually be stored in the body you don't actually store memories in the body what you store are activation of neural circuits that include brain and body and they all seem to Center back into the insula that structure that we talked about earlier this structure in our brain that has a map of our body's surface so contrary to popular belief we don't store memories in the body or trauma in the body in a way that for instance working out a knot or a pain in one's lower back will relieve the trauma it sometimes can activate a memory of the trauma but when one is doing that what you're really doing is activating neural circuits that reside within the brain within the insula that correspond to Sensations within the body”