Your shoulder joint is prone to a variety of complications resulting from injury or a lack of use. One of the common symptoms of a shoulder problem is popping, whether that's during a workout or from general movement. Take steps to build up strength in the shoulder and prevent it from popping.
Every time your shoulder pops, whether it feels unstable or not, you are raising the risk of dislocation. Exercises or movements that cause the shoulder to pop should be discontinued until a doctor can diagnose the problem or you can build up strength in the area to eliminate the popping.
The rotator cuff holds the ball of your upper arm bone in the socket through a series of interconnected muscles, ligaments and tissue. Doing exercises that build up this area will help eliminate popping. Low-impact exercises that work on internal rotation (rotation in to the body) and external rotation (rotation away from the body) are beneficial. Using a low-impact, controllable resistance source like a band may be all that's required. Resistance bands can be tied off on doorknobs and used to bring the forearm into and away from the body while the upper arm is braced against your rib cage for stability.
The shoulder, when it's not conditioned, can lose muscle mass and become misaligned. When this happens, popping occurs and dislocation becomes more likely. Doing simple isometrics like pushing the scapulas in your back together and holding them tight for 5 to 10 seconds at a time will help train these muscles and keep them in alignment.
Keeping the upper arm tight against the body for support is an important part of building the shoulder and avoiding popping and dislocation. Horizontal curls with light dumbbells are another form of internal rotation. Lie down on your side with your popping shoulder on the bottom. Bend your elbow so it is perpendicular to your body, palm up holding the weight. Bring the weight up to your chest. You can also do this as a external rotation by laying on your side with your bad shoulder up. The forearm should be bent at 90 degrees, with the upper arm once again tight to the body. With the weigh against your chest, bring your forearm up so it is perpendicular to your body.