An assessment is required first to be sure if it is a Sacrum ligament issue as it is not very common. If it is diagnosed then hip and core stability exercises will help. Bridging , Bent leg kick ups in all fours , Deadbug are a few exercises which should be done under Physio guidance and supervision
Next Steps
Seek a Muscusloskeletal Physiotherapist for proper assessment
Health Tips
Random exercises can increase the pain