The causes of hamstring pain behind the knee include meniscus injury, arthritis, lumbar disc herniation and so on. 1. Meniscus injury: If you squat under weight for a long time, it may continuously press the meniscus, which may lead to meniscus injury and symptoms of soreness in the hamstring behind the knee. 2. Arthritis: When inflammation occurs in the knee joint, it is easy to cause irritation to the joint capsule and the surrounding muscle tissues, resulting in soreness in the hamstring. At the same time, it may also be accompanied by limited movement of the knee, swelling and other symptoms. 3. Lumbar disc herniation: Lumbar disc herniation is mainly caused by degeneration of the intervertebral discs, which will stimulate the nerve roots and produce radiating pain, and then the symptoms of hamstring pain may appear. Soreness in the hamstring behind the knee is a relatively common phenomenon, and if the symptoms persist for a long time, you should pay attention to them and seek medical treatment as soon as possible.