This is a common myth. Those cracking sounds are generally caused by gas bubbles moving within the joint fluid and are not harmful. After all, our joints are meant to move freely all the time.
However, it’s not advised to crack your back on your own or force it into strange positions. Cracking your back or neck too frequently or forcefully may cause discomfort or strain in the surrounding muscles and tissues. Additionally, if done incorrectly or without proper training, self-manipulation of the spine can potentially cause injury, including damage to the ligaments or nerves.