The looseness is usually a results of repetitive overhead movement when swimming and participating in tennis, for example.  The symptoms of shoulder instability are clear, so If you're enduring any of these, it is actually highly recommended to go to an orthopaedic surgeon early to prevent your affliction from worsening.  https://www.theorthopaedicandpainpractice.com/what-are-shoulder-joint-dislocations/?_gl=1*164kc8h*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB