Lower back pain is one of the most common reasons patients visit primary care physicians. The Ministry of Health recognizes it as a significant public health issue due to its high prevalence and the substantial healthcare costs it imposes.70-year-old patient. Retired nurse. Medical history: benign prostatic hypertrophy. Three-month history of progressively worsening lower back pain, aggravated by physical activity, accompanied by asthenia. Self-medicated with first-step analgesics with partial improvement. Physical examination revealed moderate lumbar tenderness without radiculopathy and tenderness of the anterior wall of the left hemithorax. In light of the prolonged symptom duration, the patient’s advanced age, and the presence of systemic manifestations, further diagnostic investigations were undertaken. Laboratory findings: normocytic-normochromic anemia, renal failure, hypercalcemia. Imaging tests: lumbosacral spine X-ray: no apparent alterations. CT scan : mass in the upper left chest wall, with lysis of the anterolateral region of the left third rib, measuring 7 x 4.4 cm in the axial plane. Several vertebral and sternal lytic lesions, the most evident of which was the vertebral transverse process (T8). Grade II compression fracture of T4. Lytic lesions of the sternum.The combination of chronic back pain, anemia, renal dysfunction, hypercalcemia, and multiple lytic bone lesions suggests multiple myeloma with skeletal involvement. The patient was finally diagnosed with IgA kappa IIIA Durie-Salmon/International Staging System II multiple myeloma with treatment criteria for bone lesions.One of the common presentations of multiple myeloma is bone pain, which can be mistaken for other degenerative skeletal conditions, potentially delaying diagnosis. There is a Cochrane database review on "Red flags to screen for vertebral fracture in people presenting with low back pain" that may be useful in our practice.This case underscores the importance of careful evaluation of elderly patients with new-onset back pain and systemic symptoms, highlights early recognition of red flags, and emphasizes the role of primary care physicians in initiating timely investigations and coordinating management for serious underlying conditions.The primary care physician plays a crucial role in the early diagnosis of multiple myeloma, thereby contributing to improved survival and quality of life.   Keywords: multiple myeloma, hypercalcemia, low back pain.