“L5-S1…moderate lateral recess stenosis and neural forminal narrowing on the left with impingement on the l5 and s1 nerve roots on the left…L4-l5 4 to 5 mm left paracentral disc protrusion with moderate neural foraminal narrowing bilaterally with indentation on l4 nerve root greater on the left than right”.
It appears that you have a herniated disc, lateral recess stenosis and foraminal stenosis on the left at L4-5 and L5-S1. This problem becomes more symptomatic when you stand as the nerve hole narrows when you stand. See these hyperlinks to understand:
https://neckandback.com/conditions/foraminal-collapse-lumbar-spine/
https://neckandback.com/conditions/lateral-recess-stenosis/
https://neckandback.com/conditions/herniated-disc-lumbar-spine/
You more likely need a surgical workup which consists of diagnostic blocks and possibly surgery.
Dr. Corenman
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.