New knee pain

[FairyPoppins]

Over the last week I've had worsening pain in the area of my kneecap...
It's fine when I'm walking and sitting, but if I kneel or am in a position where the back of my calf is close to the back of my thigh, there's a sharp stinging pain.
There's no swelling or broken skin, but the pain is definitely getting sharper...
Hoping someone might have experienced similar?

I am having this exact issue right now! Started a week ago, at first I thought I was kneeling on a sharp object like a pebble. It's my left kneecap as well, and it only hurts when I'm kneeling on a hard surface.