Welcome to the board. This is a tricky question as many issues that originate in the back do not produce localized back pain. I had very bad sciatic pain running down my leg for over 3 years before I finally agreed to have surgery. I never had back pain.
Groin pain is tricky because there are so many muscles, ligaments and nerves that feed that area, the buttocks, the pelvic floor, etc. Under the best of circumstances, spinal specialists have trouble figuring out what is causing the pain.
Do you know when the pain started? Did you do any activity that might have caused the pain? Try to reconstruct the time frame prior to the onset of the pain. If it is a ligament or muscle, hopefully with rest it will go away fairly soon. If it is a nerve that is being compressed, it usually takes a lot longer to heal. Does it hurt more when sitting? Standing?
You might try researching "pudendal nerve or pudendal neuropathy" and see if that sounds like what you're experiencing....
Hopefully you just stretched a ligament and it will heal quickly.