Hi, Yesterday while shopping I bent down to pick something up, and had sharp pain in lower back, just left of spine. Still got pain now.?

Acute back pain. You’ve experienced an acute lower back pain (obviously). Two possibilities. More likely, you pulled a muscle which is now in an intense and painful spasm. Also possible, you may have herniated or swelled a disc acutely when you started to come back up again with the item you were lifting. If you’re having numbness or tingling down your leg(s), you may want to seek medical attention. .
Low back strain. your symptoms strongly suggest a musculoskeletal origin to your painthe onnly accurate way to deal with this situation is to see a physician to be assessed by physical examination.
It will settle down. Back pain like yours is fairly common but usually goes away in 2-3 weeks provided you give your back muscles some rest. This is most often muscular in origin....sometimes it can be a disc sprain...but either way the body has remarkable ability to heal. You need to give your back rest, apply local heat(warm water towel soaks) and take paracetamol/Tylenol as needed.