Knee pain is a frequent complaint. It can sometimes be concerning, particularly if it is very sore. However, knees often respond well to specific exercises and the pain is rarely caused by something serious. The knee is built to be very strong and is good at holding your weight, walking, and jumping (especially when the surrounding muscles are strong). It is very difficult to damage.
Most knee complaints will improve with time and some simple steps to strengthen it. At times it might not feel that your knee can get any better, but very few people need any extra care other than the steps below.