These are injuries sustained while performing routine daily activity such as bending over to pick up a child or moving a box. There are also the twisting and turning in any single direction that can overload soft tissue.
Injuries happen quite gradually. Your body tries to compensate causing postural and biomechanical distortion.
Symptoms then come on when long held compensation patterns cause an imbalance, where one group of muscles become stronger than another, to either cause compression or drastically reduce range of movement.