The pain in the flesh of the arm may be caused by the following: 1. chronic strain on the local muscles and soft tissues, or aseptic inflammation, commonly seen in people who do heavy physical work for a long time on the arm, or often do sports. 2. the day before the pain, after the arm has done a long period of strenuous exercise, resulting in the accumulation of local lactic acid on the muscles, stimulating the muscles to appear 3, cervical degenerative changes caused by cervical spondylosis, such as osteophytes, herniated discs or small joint misalignments, which compress the nerve roots of the upper limbs, can also appear in the upper limb neuromuscular, pulling pain, numbness, weakness and other sensations.