What can i do for my pain in my left knee?

Rest it: You can try otc meds for pain, try resting it, compressing with an ace wrap, icing it if helpful. But the best thing you can do is see a dr. And get properly diagnosed so the best treatment can be started. Good luck.

Ice.: Ice the knee for 20 minutes at a time, 3-4 times per day. Also, if you can take an over the counter anti-inflammatory medication, like aleve, (naproxen) it should help.

Many possibilities: Need more information including - specific location of pain in knee; severity of pain; quality of pain; associated symptoms - numbness, tingling, weekness; exacerbatiing factors; relieving factors; what tried; history of similar symptoms; recent trauma.