Shoulder pain can usually be pretty tricky to diagnose because of the complicated nature of the shoulder joint. I recommend that you contact your physician. For the sake of explanation, I will explain the shoulder joint anatomy. The shoulder joint itself can be thought of as a horizontal 'ball and socket' configuration similar to a golf ball sitting on a golf tee (socket). The golf ball is formed by the head of the arm (humerus), while the socket is formed by the glenoid (which is connected to your shoulder blade. As with a golf tee, the glenoid is fairly shallow, and hence shoulder stability (i.e. ball stays on the socket) depends on several mechanisms. Firstly, there is a soft tissue lip that lines the rim of the glenoid (called the labrum), which essentially deepens the glenoid, allowing for greater stability. Secondly, the rotator cuff muscles are a group of four muscles that surround the shoulder joint, and are responsible for stabilizing the shoulder (imagine rotator cuff as four rubber bands that tie the gold ball to the tee) and for shoulder movement. Traditionally, the 'shoulder' can also include some of the larger muscles that also surround the shoulder joint, including the deltoid and the trapezius muscles. That said, dislocation represents the humeral head (golf ball) shifting completely off of the glenoid (tee). In this case, often shoulder movement at all is prevented, and the arm is usually held pretty strictly at the side of your body due to pain and a physical inability to to move the shoulder joint. Often an easy clinical way to see if your shoulder is dislocated is the ability of that same hand to touch the opposite shoulder; that is, if you can touch your Left shoulder with your Right hand, then your Right shoulder is likely not dislocated. I suspect that since you can move your shoulder, your shoulder is likely not dislocated. Injury
to the shoulder, then, can be due to tearing of your labrum or injury to your rotator cuff muscles, which can feel like popping. If these conditions apply to you or someone you know, please contact your physician or call 911 in cases of emergency.