Can you help me identify my knee issue?

Hey all, I wanted to ask about a some knee pain I've been experiencing.

It seems to mainly manifest when I engage in "leg extension" type moves. Not that I do leg extensions on the machine or anything...

It's weird... I could do weighted squats just fine, but sometimes, I'll be sitting on an office chair, and propel myself back, and THEN I'll feel it in my left knee. It's like, a semi-sharp thing under the kneecap.

Possibly related: My knees click a lot. If I'm standing around, and I lightly lock and unlock my knees, more often than not, it'll "click" audibly, kinda like the sound of cracking knuckles.

Sometimes I'll feel the aforementioned knee pain more than other times, and usually, one "click" will relieve it somewhat.

When I'm climbing stairs, there's no audible clicking, but I can "feel" it clicking a bit with every step up I take, and hear like a high-pitched version ripple through my body... if that makes sense...

Is this something familiar to anyone?

p.s. I've scheduled an appointment with a PT, but wanted to get the hivemind's perspective too.

In general, I have some amount of hypermobility (most noticeable in my shoulders, which dislocate super-easily, if in a precarious position like attempting an overhead squat), and the occasional lower back pain... I wonder if that's all linked, or if this is separate... It'd be good to know if there's an overall thing that's exacerbating this, or if the knee issue is isolated.