There are several possible causes of arm swelling and pain: 1. Chronic strain injury, if a posture is maintained for a long time or the same job is repeated constantly, elbow tunnel syndrome or carpal tunnel syndrome may occur, mainly because the local nerve vessels are constantly squeezed and worn, thus causing redness, swelling and pain in the arm. For treatment, we can give Fotarine to relieve the pain, Micropress to nourish the nerves, and give physiotherapy such as Chinese medicine patch and Chinese medicine fumigation to relieve the symptoms. The main clinical symptoms are fever, local swelling, local pain, and ultrasound can confirm the diagnosis. The main clinical symptoms are fever, local swelling and local pain.