Pain at Knee

I've already MC for 3 days due to my knee pain and doctor say it could be the joint or uric acid that cause the pain. The doctor take my blood for test and I will see her again on Friday. She gave me 'Pain Killer' and anti-gastric medicine. My knee pain when I bent my legs especially when standing up from the seat, walking up and down the stairs. Any movement that bent my knees will be pain. Even I have to walk slowly on a flat path. I remember on Monday morning, when I woke up, my legs were like disabled and couldn't move until I force it to move and feel the pain.

This is not the first time my knee pain. Few weeks ago the same situation happen but I think maybe I did more cardio at gym that caused the pain and I just ignored it, go to work as normal, climb up and down the steps at LRT station. I just stand the pain. But this time was different. My last gym was on Saturday evening. The pain starts on Sunday night. It's more than 12 hours gap. Maybe doctor is right, I have to wait for the blood test report and see what happen.

This is a pic of my painful left knee: