You have most likely a torn ligament or slip disk or both in your back. You should take rest for atleast 3 weeks. Avoid lifting weights an avoid bending forward for 5 to 6 months.
Next Steps
If pain comes back repeatedly, you need to get an MRI scan done. Visit an orthopaedic doctor nearby.
Health Tips
Use a Lumbosacral belt for a month to get better sooner.