Welcome to Health Care Magic
Hope you are doing good. You should do X-Ray knee joint. Common knee injuries vary from minor falls which may settle down in a few days to major accidents which may take months to recover from. The knee ligaments and cartilage
are the structures most commonly damaged.
There are 4 ligaments in the knee, which work in the pairs. The anterior cruciate ligament
and posterior cruciate ligament
control the forwards and backwards movement of the knee and are really important for providing stability. The medial and lateral collateral ligaments provide sideways stability for the knee.
Ligaments are usually injured either by sudden twisting movements, or when a great deal of force goes through part of the knee eg from a sporting tackle. You could have a better idea once you do x-ray knee joint.
Hope you are satisfied with the answer