Groin pain can be due to different cause like, muscle pull, muscle strain, hip joint capsule impingement, and many more.. as u mentioned, if the pain started suddenly due to any jerk, high impact activities or injury , it must need rest for 2 to 3 week to heal or recover. Which need frequent ice application also. Then the rehab or stretch etc start.
Next Steps
consult Ortho/ sports medicine/ physiotherapy doctors for reassessment and recovery plan. examination of painful movement and position.
Health Tips
do not stretch your injured muscle if there is no tightness.