Knee pain generally comes on slowly, as an effect of strenuous activity or heavy lifting from the usual. Such kind of knee pain can generally be taken care of at home. However, if you sustain a minor injury, then you need to observe it for a day or two carefully. If none of the home remedies doesn't work out, then you should go and see a Knee Doctor.
Here are a few options you should try when you feel Knee pain:
Rest: Resting is usually the way out when you are feeling pain. As it restricts you from any strenuous or painful activities. This gives your knee time to heel.
Using Ice packs: While resting, you can put ice packs on your knee for 15-20 minutes a few times every day. You can use ice cubes wrapped in a towel for creating the pack.
Compression: Wrap your knee with an elastic bandage to help control the swelling. However, make sure not to fit the bandage too tightly around your knee; otherwise, it may cause more pain, or your leg will swell.
Elevation: Sleep on your back with your knee propped up on pillows. This may help control swelling and pain.
NSAIDs: These are nonsteroidal anti-inflammatory drugs which help relieve pain but shouldn't be used without prior doctor recommendation.
If you have long-term knee pain due to arthritis, then you should lose weight and exercise to strengthen your muscles.
If none of the above methods helps reduces pain, then it's definitely time to visit a Knee Doctor.