Effect of Stellate Ganglion Block on ME/CFS

Inclusion Criteria: * Age (18-50 years) * Female * ME/CFS (CCC and IOM criteria) duration less than 4 years at time of study enrollment * Confirmed or suspected viral disease prior to ME/CFS onset (e.g., SARS-CoV-2, Epstein-Barr, Influenza) * BMI =18-29 kg/m\^2 * Ability to read, write and speak English language Exclusion Criteria: * Prior SGB treatment * Allergy to amide local anesthetics (e.g. ropivacaine, bupivacaine) * Current anticoagulant use * History of bleeding disorder * History of glaucoma * Infection or mass at injection site * Anatomical abnormalities in C3-T1 region * Current pregnancy * Hypertension * Diabetes (any type) * Thyroid disease * History of neck or throat surgeries * Vocal cord problems or paralysis * Causalgia/Chronic Regional Pain Syndrome (CRPS) * Current cancer diagnosis * Diagnosis of Guillain-Barré syndrome * Diagnosis of current moderate or severe substance use disorder * History of neurological disease, seizure, or significant head trauma * Conditions or disorders (other than ME/CFS) that affect cognitive functioning including stroke, past or present diagnosis of psychosis or psychotic symptoms, diagnosis of bipolar I disorder, or severe depression