Soreness from the right shoulder to the arm may be related to the following causes: 1. The most common is caused by peripheral neuropathy, such as in the onset of neurogenic cervical spondylosis and thoracic outlet syndrome, due to the stimulation of peripheral nerves, then there may be radioactive pain in the path of nerve travel, from the neck and shoulder all the way to the hand may appear a certain degree of soreness. 2. This condition may be caused by overexertion, such as excessive exercise or heavy lifting, which may cause muscle fatigue in the right upper extremity, followed by soreness when resting. 3. This condition may be caused by inflammation of the joints in the right upper extremity, such as in the case of severe frozen shoulder, there may be soreness in the shoulder and below it. 4. This condition may also be caused by inflammation involving multiple joints throughout the body, for example, during the onset of rheumatic or rheumatoid arthritis, which may cause soreness in the entire right upper extremity.