• total number of headache days per month [ Time Frame: through study completion, an average of 2 years ]
  To evaluate improvement in total number of headache days per month, acute pain mediation used based on number of doses of medication taken from baseline period to end of treatment phase, and to end of follow-up phase in the same cohort.
• quality of life based on change in Headache impact test-6 (HIT-6) [ Time Frame: through study completion, an average of 2 years ]
  To evaluate the impact of headaches on the quality of life measures (pain and disability) based on change in Headache impact test-6 (HIT-6) from baseline period to end of treatment phase, and to end of follow-up phase in persistent PTH. The six-item Headache Impact Test (HIT-6) provides a global measure of adverse headache impact and was developed to use in screening and monitoring patients with headaches in both clinical practice and clinical research. A total HIT-6 score ranges from 36 to 78: Little or no impact = HIT-6 score 49 or less; Some impact = HIT-6 score 50-55; Substantial impact = HIT-6 score 56-59; Severe impact = HIT-6 score 60.
• acute pain medication use [ Time Frame: through study completion, an average of 2 years ]
  change in acute pain medication use based on number of doses of medication taken from baseline period to end of the treatment and follow up phase
• phq-9, bai, plC-5, pcs and insominia survey [ Time Frame: through study completion, an average of 2 years ]
  part of the QoL measures to evaluate the impact of headaches.
• 50% reduction in headache frequency [ Time Frame: through study completion, an average of 2 years ]
  percentage of participants with 50% of more reduction in monthly headache days will be evaluated.

• total number of headache days per month [ Time Frame: through study completion, an average of 2 years ]
  To evaluate improvement in total number of headache days per month, acute pain mediation used based on number of doses of medication taken from baseline period to end of treatment phase, and to end of follow-up phase in the same cohort.
• quality of life [ Time Frame: through study completion, an average of 2 years ]
  To evaluate the impact of headaches on the quality of life measures (pain and disability) based on change in Headache impact test-6 (HIT-6) from baseline period to end of treatment phase, and to end of follow-up phase in persistent PTH. The six-item Headache Impact Test (HIT-6) provides a global measure of adverse headache impact and was developed to use in screening and monitoring patients with headaches in both clinical practice and clinical research. A total HIT-6 score ranges from 36 to 78: Little or no impact = HIT-6 score 49 or less; Some impact = HIT-6 score 50-55; Substantial impact = HIT-6 score 56-59; Severe impact = HIT-6 score 60.

• Persistent Post Traumatic Headache
• Mild Traumatic Brain Injury

• Experimental: treatment arm
  tDCS treatment group
  Intervention: Device: transcranial direct current stimulation
• No Intervention: control arm
  Sham tDCS

Inclusion Criteria:

1. Verified history of mTBI
2. Persistent PTH as defined by International Classification of Headache Disorders (ICHD) III diagnostic criteria("Headache Classification Committee of the International Headache Society (IHS) The ICHD, 3rd Edition 2018).
3. Verification of headache frequency through prospectively collected baseline information during the 28-day screening/baseline phase.
4. Not currently taking a migraine or headache preventive medication OR has been taking a stable dose of a preventive for at least 60 days prior to screening and agrees to not start, stop, or change medication and/or dosage during the study period.
5. The investigators will include medication overuse headache as defined by ICHD III diagnostic criteria.
6. Participants is either not of childbearing potential, or if they are of childbearing potential, they agree either to remain abstinent or use (or have their partner use) an acceptable method of birth control for the duration of the study.
7. Male or female, age between 20-60 who demonstrates compliance with the electronic Daily Headache Diary during the 28-day baseline phase as defined by entry of headache data on a minimum of 22 to 28 days (80% diary compliance).

Exclusion Criteria:

1. Unable to complete headache diary as required by protocol.
2. Any psychiatric condition with psychotic features, and/or any other psychiatric disorder not stable or well controlled, that would interfere in the ability to complete study activities
3. Received onabotulinumtoxinA, cognitive behavior therapy, physical therapy or any other form of non-pharmacological therapy for headaches during the 4 months before screening.
4. Has a planned military deployment within the 6 months post screening.
5. Active substance abuse within last 4 months.
6. History of seizure, stroke, multiple sclerosis or other unstable neurological condition or a significant abnormal neurological examination.
7. Unable to tolerate tDCS stimulation.
8. Have any other conditions that in the judgment of the Investigator would make the participants unsuitable for inclusion or interfere with participating or completing the study.