The study will evaluate the clinical efficacy and performance of the BTL-043 device for alleviating back pain. The study is a prospective, multi-center, open-label, single-arm study. Subjects will be required to complete four (4) treatment visits and two (2) follow-up visits. All of the study subjects will receive the treatment with the subject device. At the baseline visit, the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and the Quebec Back Pain Disability Index (QBPDS) will be administered. The subject's weight and height will be recorded. The treatment administration phase will consist of four (4) treatments, delivered 2-10 days apart. Therapy time is set to 30 minutes for each treatment. After the last treatment, the subjects will receive the ODI, QBPDS, and the Therapy Comfort Questionnaire to fill in along with the VAS. During the 1-month and 3-month follow-up visits, the subjects will fill in the Subject Satisfaction \& Quality of Life Questionnaire, in addition to the ODI, QBPDS, and VAS. Safety measures will include documentation of adverse events (AE), which will be assessed after each procedure and at all follow-up visits.