While i was working out i was doing barbell rows. i felt a sharp pain in my lower back.the next day it was nearly impossible to lean forward.i took a rest from going to the gym for like 2 weeks.my back was getting better and i could lean and touch my toes easily but with a bit pain. when i started working out again. the same thing happened and the pain came back. now i rested for like 3 weeks and my back is much better but with a bit pain only when i wake up. when can i start lifting&what to do