Thanks for posting your query.
From description , it seems you might suffering from soft tissue injury
or ligament injurry at knee.
I would suggest getting this evaluated by an orthopedician for an accurate diagnosis and appropriate management. You may get the MRI
of the area affected under his/her guidance.
In the interim, continue using knee brace
,anti-inflammatory drug like motrin
to reduce pain and inflammation. Avoid putting weight and rest well.
Wishing you good health.
Dr Saurabh Gupta.