While there are many reasons a person may begin experiencing knee pain, there are some causes that are more common than others. Knee pain can often be the result of repetitive stress on the joint, or because of a specific traumatic injury. Arthritis can often cause chronic pain and inflammation, especially in older individuals. Meniscus tears, ACL injuries, and ligament strain are also relatively common, especially for people who lead active lives or who are athletes. For patients with arthritis, there is no specific cause that can be pinpointed as the cause of their condition. Rather, repetitive use can simply lead to dull, aching pain that becomes increasingly worse.