Pain on inside of knee, full movement etc

A few months ago I stepped In a odd way while playing tennis. The knee gave me a little “jolt” - I didn’t think much about it at the time. So currently I have full movement, hardly any issues during the day. At night while trying to sleep the pain feels like a small ice pick and to help relieve pain I lay on my back and bend the knee towards the ceiling.
Thoughts? Since a have full mobility etc. I don’t understand what the pain is coming from?
No swelling or discoloration etc