Muscle tendons in the shoulder can be torn from the stress of repeated motions, such as your golf swing. There are other causes, too, including over-exertion and physical injuries such as falls and collisions. If you do tear a tendon, you should consult a physician to create a plan of care. That said, it's also simple to treat it yourself both before and after your doctor visit.
Have your shoulder examined by a doctor as quickly as possible after you injure it. If the tear is serious, your doctor might determine that surgery is required to fully repair it. Even if there is no need for surgery, only a doctor can give you customized care and rehabilitation instructions, as well as prescribe medicine to manage pain and optimize healing.
Minimize movement of the injured shoulder for the entire duration of the healing process. Your doctor will be able to give you an idea of how long it will take your injury to fully heal. If you think you'll have a hard time keeping the shoulder stabilized, see if your doctor recommends wearing a sling, which you can get either from your doctor or from a drug store.
Apply an ice pack to the injured shoulder for up to 20 minutes at a time. You can do this several times a day to manage pain and reduce swelling, but you should not expose ice directly to the skin. Use ice packs through clothes or wrap them in towels first.
Take an over-the-counter anti-inflammatory pill as directed to reduce swelling. If you're taking other medications, even if they're not directly related to the shoulder injury, consult your doctor before taking anti-inflammatory medication.
Take part in physical therapy if and when your doctor says that you're ready for it. It might be tempting to start trying to rebuild your shoulder and arm strength, but you can re-injure the tendon by using it too soon. If your tendon has healed to the point that it can handle mild physical therapy, though, doing therapist-prescribed exercises regularly can help the healing process.
Consider any surgeries recommended by your doctor. Many torn tendons can be repaired with laparoscopy, which means that the incision is small and the recovery time is short. Since many torn tendon injuries can heal without surgery, however, these surgical options are usually only proposed for severe tendon injuries. If you undergo surgery, make sure you closely follow your doctor's precautions regarding the recovery process, as you can still easily re-injure the shoulder shortly after a surgical procedure.