The cracking sound that you hear when you move your back or neck in a certain way may be an air bubble forming and rapidly collapsing on itself, in itself not a harmful thing. Cracking your neck can provide temporary relief, although it's almost always best to allow a licensed practitioner, such as a chiropractor, to do adjustments.
http://www.wikihow.com/Crack-Your-NeckBe aware that cracking your own neck can have serious unintended consequences Cracking your neck could create a small tear in the lining of the vertebral artery, which eventually could lead to stroke. Understand these risks before you engage in any home remedies.
