Given the right conditions, joints can make cracking, popping, grinding or snapping noises. These kinds of noises are particularly noticeable in the neck. If you hear noises in your neck but they are not associated with pain, it is probably harmless; however, if you experience pain, you may want to visit your doctor.
The joints in your neck are surrounded by a joint capsule. That capsule is filled with a fluid that provides lubrication to the joint surfaces. In that fluid, certain microscopic bubbles of gas are present and when you twist the joint capsule, you increase the pressure on those gas bubbles and they pop through the capsule lining and make the noise you hear. This is not harmful to the joint. You'll also notice this kind of noise can't be done again until the joint gasses have time to form again.
Ligaments and Tendons
Sometimes, the noise you hear is caused by a ligament or tendon sliding across a raised surface on the bones of the joint. When you move, those ligaments or tendons get slightly caught on the raised bump and when they finally slip loose, you'll hear them snap or pop free. This kind of joint noise is usually easily reproduced every time you move your joint that way.
The type of noise that is of most concern is the grinding noise you may hear if the surface of your joints have become roughened. The concern is that the process that causes those joint surfaces to get rough is usually a form of arthritis called osteoarthritis and is an indication of degenerative changes in the joint.
Cause for Concern
Although most of the time joint noise is considered harmless, there are some times when a doctor's visit is in order. If your joint noise is accompanied by pain with movement, stiffness, warmth and swelling, or localized tenderness, you may have arthritis. Other symptoms to watch for are pain that wakes you up at night, or pain and stiffness that is worse when you first get up in the morning and gets better after half an hour. Research published in 2011 in "Rheumatology International" notes that as the baby boomers continue to age, osteoarthritis in the neck is going to become more common.