Go for x-ray and after that  start  physiotherapy treatment it will help you  an s avoid lift heavy object . Take proper rest

At night Keep pillow under the knees while sleeping supine lying, and keep pillow between the knees while sleeping side lying. U will feel better. Search google for proper sleeping position

As You Mentioned that Your Work Involving Heavy Weight, it quite Possible that you are Have Hyper toned Back Muscles which Blocking Nerves System Sympathetic Flow. Probably You Need Myofascial release followed By Manual Mobilization... As Home treatment You can Follow McKenzie Exercises.

Take an X-ray of LS and check if there is any disc bulge or nerve compression. Visit nearest physiotherapy center ask to apply IFT+US. Take this for a week, the pain will reduce, untill then avoid lifting heavy objects, wear LS belt. take rest as much as possible. At home can apply hot water fermentation for quick relaxing of muscles.