It's like opening a soda can or removing a suction cup. The sound is interesting, but isn't a guide to the quality or value of the adjustment. Pain is a warning sign. Like the piercing sound from a smoke alarm, the alarm isn't the problem. The alarm has a cause, just like every ache or pain has a cause.
Some people choose to cover up the pain, instead of correcting the cause.
The nerve-rich facet joints on the back side of each spinal bone are a common cause of back pain. The discs between spinal bones can be a source of back pain, too. Trauma can cause the soft, pulpy material in the middle to bulge or herniate, putting pressure on delicate nearby nerves. Once you know the cause, you have several choices. One approach is bed rest.