Pain in the knee can be caused by many things, including ligament strains, tears, etc.  I have OA in both knees.  My knees hurt a lot, especially when walking upstairs. I have bakers cysts in both knees, i.e. the back of both knees are swollen and paintuf to the touch.  Both knees creak and pop.  One knees "crunches" when I walk up stairs.  I would suggest resting your knee and perhaps taking some anti-inflammatory drugs, if you are medically able to do that.  They tend to upset the stomach if taken for too long of a time. If the pain doesn't improve in a week, I would make an appointment w/a doctor.  I am NOT a doctor or healthcare professional.  Just my two cents worth.

Best Wishes,

V