Study of Low-dose Naltrexone in Chronic Migraine With Fibromyalgia

Inclusion Criteria: * Subjects will be adults of all genders ages 18 and older. * Patients with a diagnosis of CM (with or without NDPH) by IHC-3 criteria, diagnosed by a certified headache specialist. * Subjects who received a new prescription for LDN * Fibromyalgia-diagnosed according to Fibromyalgia Rapid Screening Tool * Subjects should be on stable headache and migraine preventives for the past 2 months with no plans to change medication for the next 4 months. * Subjects willing to maintain a headache/migraine diary one month prior to taking medication and while taking the medication, either physical or electronic diary of their choice. * Subjects willing to fill out pre and post intervention surveys * Subjects willing to comply with planned follow up phone calls and visits. Exclusion Criteria: * Not planning on follow up care with clinician. * Patients with decreased decision-making capacity in which the investigator's opinion would interfere with the person's ability to provide informed consent and complete study questionnaires.