The first thing you should do is to identify the cause of the knee pain, and then target physical therapy, medication, and surgery. Caused by sleeping on the knee pain can not move the cause of muscle strain, meniscus injury, rheumatoid arthritis, it is recommended to identify the cause of the disease before treatment, targeted treatment. 1. Muscle strain: If the patient is usually engaged in heavy physical work caused by chronic muscle strain, long time sleeping on your back is easy to cause local muscle blood circulation is not good pain, you can carry out the appropriate hot compresses to relieve pain. 2. Meniscus injury: if the patient meniscus damage, when sleeping on the stomach can also appear knee pain can not move, the injury time is shorter can be iced, you can take non-steroidal drugs, such as ibuprofen for anti-inflammatory pain, if there is a meniscus tear also need to carry out surgical treatment. 3. Rheumatoid arthritis: If the patient’s rheumatoid arthritis acute attack, also easy to cause knee joint pain can not move, you can take diclofenac sodium and other drugs to relieve the pain, but also the use of methotrexate to control the progress of the disease, but also the use of biologics to control inflammation. Caused by sleeping on your back knee pain can not move more reasons, but also may be related to gout, fractures, osteophytes and other reasons, if the symptoms continue to have no relief, it is recommended to go to the hospital in a timely manner to find out the cause of the disease, by the doctor targeted treatment.