Hi, for ur question it seems to be like an muscle pull only, did u started ur pain after lifting any heavyweight from floor means there is a chance of nerve injury, so I need some little more details about ur patter of pain, duration of pain, sudden or gradual start of pain, do u feel night pain? If u answer these questions too I can give u the diagnose and remedy for ur pain. Till then apply ice fermentation to that part for 10 min for 2 times a day as it will heel the part, when comparing to hot fermentation ice gives better result in healing process.

Helloo.. Low back ache usual causes are Spinal cord issues like dic prolapse/bulge with root compression or nerve impingement.. Urinary tract infections, Renal stones,ureteric stones Muscle spasms... Trauma It's better you consult an orthopaedician and get examined once.. You can use hot fomentations for pain relief