Hello, this is caused by compression of the brachial plexus as the performance
Opinions and suggestions:
The brachial plexus can lead to oppression of the reasons could be cervical spondylosis or a tumor, so that this situation is to go to hospital to be a system of checks to see clearly after the cause is more appropriate course of treatment.
There are many causes, such as arthritis, poor circulation, osteoporosis, carpel tunnel, retaining water, etc. You should really see your doctor to find out what is going on.