Re: shoulder injury
If the pain is on the top of the shoulder over the area near where the tip of the collar bone is located you may have strained (torn) the acromioclavicular joint (A-C joint). If it clicks repetitive or several times in a row it is usually tendon snapping over a bone. A joint pop or click with generally not do so more than once without a rest period. Look in the mirrow to see if there is a bump on the top of the shoulder-if so I'd get the A-C joint checked. That's the infamous separated shoulder they talk about in sports.