If the arm is sore and uncomfortable and cannot be straightened after dumbbell exercise, it is likely to be too much exercise and local muscle strain that causes soreness and discomfort. It may also be a local lesion that induces pain and discomfort after lifting dumbbells. The local appearance should be observed for any obvious redness, swelling, or abnormal masses. If there are no obvious abnormalities in the appearance, bilateral symmetrical pain and discomfort, you can rest first and pay attention to observation. Pay attention to local hot compresses and massage, and you can take appropriate painkillers, such as meloxicam tablets. If the soreness is caused by excessive exercise, it can be relieved significantly in 2-3 days after rest and symptomatic treatment. If there is an abnormal local appearance, such as redness, swelling, lumps, or other problems, you need to go to the hospital for examination as soon as possible, such as taking pictures and other tests.