After a couple of ACL surgeries over the years due to sports injuries and regular knee pain ever since when exercising, descending stairs etc., I was looking into the option of a combined hyaluronic acid/PRP (platelet-rich plasma) injection - about which I'd heard great things - until I realised I didn't want to take the risk after the two half-botched operations I'd had done years ago. So I decided to simply take hyaluronic acid orally on the off-chance, and have had no pain since. Could be a coincidence but it could also be worth a try. Readily available in capsule form from multiple sources. No contraindications to my knowledge, but if you're taking anything else it'd be best to make sure.
By the way, usually pain with stairs involved is from the patella or knee cap. Does that sound right?
Sorry about your knee pain. I guess the easy . . . well, not easy . . . but obvious thing is to begin working on your weight loss. I don't say that lightly, I've had to do the same and know it's hard. It takes effort and frankly, sometimes it feels like all I've got is my frig to get me through the day. ha ha. But I have tried really hard to work on this and noticed lots of things were better when I lost some weight. My gerd was better, my body felt better and my knees! So, just having that as an ongoing goal would be good. So, is there any coverage for you insurance wise to see a physical therapist? they can show you stretches and exercises to do to help strengthen the knee. And Ibuprofen is good for reducing swelling/immflamation and pain. My pt has told me to take 4 200 mg tabs of ibuprofen. I was reluctant but they felt it would help. Another thing I use is arnica cream bought at the drug store. It's holistic and hey, why not? It always seems to help. I like the icy hot type patches too. But your best bet is to go see your doctor and then a physical therapist to get some exercises to help mobility and strength. good luck!