The reasons for the aggravation of frozen shoulder pain at night may include increased self-perception, slowed blood circulation and cold shoulders. 1. Enhanced self-perception: As the surrounding environment is quieter and the attention is easy to concentrate at night, it is easy to enhance the perception of one’s own shoulder pain, so the pain is felt to be aggravated at night. 2. Slowing down of blood circulation: At night when you sleep, your body is in a state of rest, the tension in the smooth muscle of the small blood vessels is high, the blood flow is less than during the day and the blood circulation is slowed down, which makes the inflammatory substances gather and increase, which may aggravate the pain. 3. Cold shoulder: The shoulder is exposed for a long time at night, which can easily lead to cold shoulder area, and the slowing down of blood circulation by the cold will also increase the gathering of inflammatory substances and thus aggravate the phenomenon of pain. There may be other reasons for the aggravation of frozen shoulder pain at night, so you should go to a regular hospital, complete the relevant examinations, and follow the doctor’s instructions for standardized treatment after a clear diagnosis, so as not to delay the condition.