Knee clicking.

[Webbo2]

If it’s not painful or swollen and you have full range of motion, likely nothing to worry about although could be some wear and tear depending on how old you are.
I have arthritic knees and physio advised avoiding standing up to pedal due to the load through the knees, try sitting and using a lower gear instead!

I do try to sit but when you are hitting 20% some times you need to get out of the saddle.

 

[Milzy]

Once had a huge knock on my knee. After 6 months it started to ease. Bone must have been badly bruised. Then loud popping clicking noises happened. It was from gases trapped inside through the healing process. No more clicking now and back to full strength after 10 months.