Can you give a few more details. Like what type of work do you do? It could be strained from say heavy lifting repetitive motion. Is it your entire left side or your back?? The reason I ask my entire left side of my body was jacked up because of a job with repetitve motion. I had an mri, ct scans x-rays, physical therapy, anti-inflamatory meds, bed rest and nothing worked. I out of desperation went to a chiropractor who said my entire back was out of line. After several adjustments I am now completely out of pain. I had the sharp pains, numbness, weakness you name it.