The symptoms you mentioned usually are due to erosion of cartilage under your knee cap..With this cartilage loss you might get pain while using stairs, Indian toilet and floor activities..
But MRI done doesn't mention about cartilage loss..
The sprain in ligaments and meniscus might be an incidental finding and not related to your symptoms..
Next Steps
You should benefit with knee strengthening exercises.
Health Tips
Avoid floor activities , Indian toilet, stairs etc..