Posterior pelvic tilt  disrupts the muscle balance in our body and can cause posture problems and back pain.
Are you correcting your gait?
Are you addressing your posture when sitting and standing?
These need to be corrected for lasting improvement.

Are you addressing your hamstring snapping around your knee?

There are several exercises and programs you can follow to strengthen the core. Using a variety of exercises is key to address different parts and the whole.

Gluteus Maximus is most likely tight.