Final answer:
Based on the golfer's symptoms, the most likely cause of the low back pain is Facet Arthropathy, as it aligns with the pattern of pain experienced during certain movements and relief with particular positions.
Step-by-step explanation:
The golfer's symptoms of sharp localized pain at the right side of the low back when swinging towards the right and relief when sitting or bending to the left suggest Facet Arthropathy. Facet Arthropathy is a condition characterized by degeneration of the facet joints, which can cause pain on one side of the lower back, especially during activities that involve twisting or extending the spine. The fact that the pain is relieved by bending to the opposite side further supports this diagnosis since bending away from the pain can provide relief to inflamed facet joints. In contrast, Sacroiliac Dysfunction typically involves pain that may be more diffuse and often refers to the buttock or thigh rather than remaining localized. Spondylolisthesis could cause similar symptoms but usually includes symptoms during other activities as well, not just isolated to certain movements. Spinal Lateral Stenosis might cause more consistent pain aggravated by standing or walking, and relief would be found in sitting or flexing forward rather than simply bending to the side.