Inclusion Criteria:  History of low back pain for a minimum of 6 months daily (prior to screening), meeting the Quebec Task Force Classification System symptom categories I-III; Male or female, age equal or greater than 18 years, with no racial/ethnic restrictions; Must have a Visual Analog Scale (VAS) pain score ≥ 40 mm (of 100 mm maximum) at the baseline scanning visit (for which 0mm = no pain, and 100 mm = worst pain imaginable); Must be able to read and speak English and be willing to read and understand instructions as well as questionnaires; Must be in generally stable health; Must sign an informed consent document after a complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits and potential risks, and are willing to participate; Must have, on average ≥ 4/10 units of pain intensity over the course of a 1-2 week period prior to the brain scanning visit; Must be willing to complete daily smartphone/computer app ratings; Must be on regular opioid or NSAID therapy for at least 3 months prior to randomization (for opioid and non-opioid treatment groups, respectively), which will be up to the clinical investigator's decision.  Exclusion Criteria:  Low back pain associated with any systemic signs or symptoms, e.g., fever, chills; Evidence of rheumatoid arthritis, ankylosing spondylitis, acute vertebral fractures, fibromyalgia, history of tumor in the back; Other comorbid chronic pain or neurological conditions; Involvement in litigation regarding their back pain or having a disability claim or receiving workman's compensation or seeking either as a result of back pain; Diagnosis of current major depression or psychiatric disorder requiring treatment, or such a diagnosis in the previous 6 months; Beck Depression Inventory II score of >28; Use of therapeutic doses of antidepressant medications at unstable doses (i.e., tricyclic depressants, SSRIs, SNRIs; low doses used for sleep may be allowed); Significant other medical disease such as diabetes, congestive heart failure, coronary or peripheral vascular disease, chronic obstructive lung disease, or malignancy; Uncontrolled hypertension; Renal insufficiency; Current use of recreational drugs or history of alcohol or drug abuse; Any change in medication for back pain in the last 30 days; High dose opioid prophylaxis, as defined as > 50mg morphine equivalent/day; Any medical condition that in the investigator's judgment may prevent the individual from completing the study or put the individual at undue risk; In the judgment of the investigator, unable or unwilling to follow protocol and instructions; Evidence of poor treatment compliance, in the judgment of the investigator; Intra-axial implants (e.g. spinal cord stimulators or pumps); All exclusion criteria for MR safety: any metallic implants, brain or skull abnormalities, tattoos on large body parts, and claustrophobia; Pregnancy, or inability to use an effective form of contraception in women of child-bearing age; Diabetes (type 1 or type 2); Lactose intolerance; Allergic reaction to naproxen or any NSAID; Any untoward reaction to l-dopa or carbidopa.