I have Osgood-Schlatter in the right knee from over training when I was 17. 5% of cases stay on through to adulthood (lucky me), similar situation, causes intense pain when squatting. Difference I suppose is it apparently is curable with expensive surgery.
Do you see a lump below your patella, pretty much at the top of the knee? If you are not sure (they are not big lumps) compare it to your good knee.