BMJ Group Medical Reference
For this treatment your doctor injects a local anaesthetic into the nerves around your shoulder. This treatment seems to work if your shoulder pain is because of arthritis. It may also help with a frozen shoulder. The research hasn't looked at whether having a nerve block can help with shoulder pain caused by other problems, such as damaged tendons.
One study looked at whether having a nerve block helped people with shoulder pain caused by rheumatoid arthritis or conditions where the bone wears away. It found that the nerve block helped reduce people's pain. The people in the study were also able to do more and move their shoulder more easily. 
If you have a frozen shoulder, having a nerve block can reduce your pain.  But it may not help you move more easily.
This treatment may make you feel dizzy. And you may get pain and bruising where you have the injection. 
Arthritis is when your joints become inflamed, making them stiff and painful. There are different kinds of arthritis. Osteoarthritis is the most common type. It happens when the cartilage at the end of your bones becomes damaged and then starts to grow abnormally. Rheumatoid arthritis happens because your immune system attacks the lining of your joints.
If you have rheumatoid arthritis, your joints get painful, swollen, and stiff. Rheumatoid arthritis is caused by inflammation inside your joints. It happens when your immune system attacks the lining of your joints.
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