severe continual pain in lower left backside?

""Spinal stenosis is the narrowing of spaces within your spine, putting pressure on the spinal cord and nerves, causing pain, numbness, cramping, or weakness in the back, neck, arms, or legs, often worsening with standing/walking and improving with sitting/leaning forward, usually due to age-related wear (osteoarthritis, bone spurs, thickened ligaments) but sometimes from injury or congenital issues, managed with physical therapy, medication, and sometimes surgery""