The injury or pain you feel now is NOT a final sentence - it's a temporary state.
Whether you are just starting out, or have been active your entire life, pain and injuries happen. The long and short of it is that you are likely experiencing pain or injury because something is too stiff and strong, or something is too weak and loose.
If you're a little bit broken follow these steps until you're not anymore...
SEEK OUT A PRO THERAPIST
Sometimes problems can be solved in one session with specific drills to practice on your own to help the process.
The last thing you want to do is become more sedentary. Rest the painful motion, but introduce as much non-painful movement as you possibly can in the rest of your body, and in that area. Don't do anything that creates a sharp pain.
BUILD A SOLID FOUNDATION
Make sure the affected area has a proper foundation in the surrounding structures. This can be as simple as getting your core and hips stronger to take the pressure off of your low back or improving your neck and spine flexibility to let your shoulder heal.