Knee pain is typically caused by some type of overuse injury. This remains true with injuries that occur slowly over time as well as those quick movement injuries in a single instance. To explain that further, take an ACL tear as an example. An ACL tear is caused by an abrupt rotation usually taking place during a fall, the result was the ACL tear, not in all instances but commonly, I see a lack of proper muscle recruitment from all hamstring muscles, in equal strength, which otherwise could have avoided such injury. An ACL tear also does not require surgery in order to work properly, proper strength in the surrounding knee muscles can support the knee joint. This is not always recommended particularly for young and active individuals.
The video here is meant to give you insight on what injury you could be experiencing based on the location of the pain.
The video here is designed to give you more information on the most common form of injury and cause of pain in the knee.
The video here will tell you what exercises you should avoid if you are currently experiencing knee pain to avoid further injury.