Hi thanks for question, as lower back pain can be occur due to no. Of reasons, it can be muscle injury, disc injury or simple muscle strain due to wrong posture, weight lifting, sudden jerks etc. So first you need to find out underlying cause of injury/ pain. Which need complete examination of spine. For the mean while you start with hot water bag for 15 min, & apply some ointment, give rest to your back, & if it not getting better then  you need to visit a clinic. For more details www.proactivephysio.in