Left knee pain. To consult this with.

Hi. I have this pain on the inside or the right side of my left knee. It's been there for two weeks now. The pain started soon after one of my crossfit/ martial arts workout sessions. During workout sessions I am able to run and do squats without much pain but it hurts the most when I try to bend my knee and sit on the floor which I can comfortably to do on my right knee. After workout sessions I am fine for the next 24 hours at least, then the pain creeps back in making it uncomfortable to walk properly for the next 24 hours till the pain reduces slightly. This has been going on for the last two weeks. Once I tried sitting on the floor on my legs with knees bent and my left knee got locked and I was in total pain and unable to bring my leg to a straight position, finally when I did bring it to a straight position I felt a bone move out and in near the knee. I need some advice on what this problem could be and who would be a right person to consult this with. Thank you