Effects of Neuro-Stim System on Pain, Sleep, and Opioid Use

Inclusion Criteria: * Subjects must be inpatients (at Walter Reed National Military Medical Center) at the time of study enrollment and study device placement. * Any patient experiencing post-operative pain (visceral, somatic, or neuropathic) and has a pain score (measured via DVPRS v2.0) equal to or greater than 4 for at least 3 hours in the past 24 hours. * Has an intact external ear where device can be placed * The skin of the ear at placement site must be free of infection * The participant cannot have been on regularly scheduled central acting opioids for more than 30 days continuously leading up to the initiation of the study. However, intermittent, breakthrough opioids are permissible, but the potential subject must have a current opioid prescription. * The participant must have vital signs (HR/breathing/blood pressure) within normal limits. * Able to understand English and verbalize their pain level. Exclusion Criteria: * Have inconsistent vital signs (fluctuating, extremely low blood pressure, tachycardia, etc.) * Wear any time of implanted electrical device such as a brain shunt, vagal stimulator, pace maker, spinal pain pump, etc. * Pregnant (by results of preoperative Human Chorionic Gonadotropin or hCG urine or blood testing) * Has a history of skin allergy to metals * unwilling to voluntarily participate * hemophilia * Psoriasis vulgaris on ears