Neuromodulation + Prolonged Exposure Therapy: Evaluation of a Technology-Enhanced, Integrated Treatment for Pain and PTSD

Inclusion Criteria: * Presence of musculoskeletal, chronic, non-cancer pain with a rating of ≥ 3 out of 10 on a 0-10 on the Defense and Veterans Pain Rating Scale (DVPRS) and a pain intensity and interference score of 1 standard deviation above PROMIS normative data (see Measures section below). Symptoms will be required to be of at least six months duration and verified diagnosis in their medical chart authorized by informed consent * Diagnosis of PTSD assigned on the basis of the Clinician Administered PTSD Scale (CAPS-5) and PCL-5 ≥ 30 * willing to participate in study randomization, treatment assignment, and assessments. Exclusion Criteria: * Having a household member who is already enrolled in the study * Active psychosis or dementia at screening * Suicidal ideation with clear intent * Current substance dependence * current opioid medication for pain and/or current use of sodium channel blockers, calcium channel blockers, or N-Methyl-D-aspartate receptor antagonists, because these medications can block tDCS effects * pregnancy and/or lactation * concurrent enrollment in another pain clinical trial * tDCS or medical related contraindications such as open-injury TBI (penetrating injury), seizure disorder (independently of the type of TBI or condition causing the seizure disorder), pregnancy, implanted metal, claustrophobia * having pain that is not chronic, presence of severe and frequent migraines, fibromyalgia, or pain caused by a primary condition such as cancer.