It can be a simple lower backache due to stress on the muscles 9r it can lead to mild disc bulge leading to pain and nerve compression. Inability to bend forward , not able to walk straight, pain increases with sneeze and cough etc.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +IFT +Heating therapy +some strengthening exercises will be helpful for sure.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no long sitting /standing /walking /travelling /driving +no cold exposure +no stair climbing +no manual exertions +no weight lifting +correct posture (sit tall).