Lateral Knee Pain

I was running in the morning and squatting in the evening. During squats, I heard a pop and felt pain immediately, which ended my workout for the day.

Moving forward, today onwards, I have knee pain on the lateral side. This happens when flexing my knee and climbing up the stairs. Every time I walk or flex the knee in any way, there is a popping sensation (almost like something is rubbing against something else).

Anyone have any clue?