Make sure you’re meeting all of your body’s nutritional needs and not poisoning it too much because that shouldn’t be the case until much later. Also exercise and see a physiotherapist if you have any chronic issues with your joints before a pain devolves into an injury.

I used to have an issue with my shoulders but it turned out to just be happening because my poor posture and lack of physical activity resulted in some of the shoulder support muscles being too weak to support some things like leaning on my shoulder while lying down without suffering for it the next day. A physiotherapist gave me a short list of exercises to do and my shoulders are great today, despite it being years since I last did any of those exercises, though I do make a conscious effort to put my shoulders back into a good posture whenever I’m about to do something with them that involves force. That might have become a permanent injury if I hadn’t strengthened those muscles up and did something that caused them to tear or the joint to dislocate.