A 42 year-old warehouse worker presents with acute low back pain that began after lifting heavy boxes at work. The pain is described as a dull ache in the lumbosacral area and occasionally radiates into the buttocks, but does not extend below the knee. Neurologic examination reveals normal strength, sensation, and reflexes. Straight leg raise and crossed straight leg raise are negative. The pain is reproduced with lumbar movement and paraspinal palpation. Which diagnosis is most consistent with this presentation?