My knee aches whenever i walk, and hurts whenever i bend it. it feels like it is popping, and the pain gets worse the more im actively walking/applying weight. it randomly started yesterday while i was working, no fall, or any injury that i know of?

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It would be prudent to see a doctor. If you are overweight losing weight is essential, Wish you good health!

Your symptoms are quite nonspecific. There are various possibilities. Try resting the knee,elevate while sitting,apply cold compresses 20 minutes a few times daily and,if you can take them,anti-inflammatory meds like ibuprofen or naproxen for a week. See an orthopedic specialist if not improved.