Immune Mechanisms of Vitamin D to Reduce Chronic Pain After Burn

Inclusion Criteria ≥ 18 years and ≤ 70 years of age Admitted to burn center Surgical team has plans for surgical management of the burn wound (e.g. xenograft and/or autograft, NOTE: in some burn patients the plan will change, but if there is documentation in the note or in communication with the surgical team there are plans for surgical management then the patient will be eligible) Patients experience a thermal burn injury, not an electrical or chemical burn. Has a smartphone with continuous service >1 year Alert and oriented Willing to take study medication (6 capsules of Vitamin D or placebo) Point of care Vitamin D level <100 ng/ml Able to speak and read English Burn survivors with acute pain severity ≥ 7/10 on the Numeric Rating Scale (initial pain severity reported by the patient on screening) Total Body Surface area burned <30%. Exclusion Criteria Substantial comorbid injury (e.g. long bone fracture) Pregnancy/Breastfeeding Prisoner status Active psychosis, suicidal ideation, or homicidal ideation Requires an emergency/bedside escharotomy or fasciotomy for the treatment of burn injury. Known Child-Pugh liver disease severity classification B or C. Known chronic kidney disease stage 4 or higher (GFR≤29). No other history or condition that would, in the investigator's judgment, indicate that the patient would very likely be non-compliant with the study or unsuitable for the study (e.g. might interfere with the study, confound interpretation, or endanger patient). Intubated and sedated at time of enrollment. Hypersensitivity to Vitamin D3, ergocalciferol, calcitriol, alfacalcidol, calcipotriol Known hypercalcemia (based on routine admission laboratory assessment). Sarcoidosis Hyperphosphatemia (based on routine admission laboratory assessment) Taking Vitamin D supplements in excess of 800 IU daily.