Repetitive stress injuries can be caused by any activity or motion that you repeat frequently. As the body experiences the same pressures and stress, it can cause microscopic tears in tissue. Since the motions are constantly repeated, the tears are not able to heal as quickly as they're being made. These tears can lead to inflammation and pain in the affected areas. Workers who have poor posture or work with tools that vibrate are often at a higher risk of developing a repetitive stress injury.