Knee Pain (runners knee?)

Hi, I’ve been training for the Brooklyn half marathon in May (with it being my first half) and have noticed some right knee pain on my last run. It is mostly prevalent when going up/down stairs, walking for a very long period of time, and some movements (like weight only on the right foot and then bending) or coming up from a squat. I’ve taken almost a week off now to give it time to rest but feel like I need to keep training as I haven’t gotten in much mileage yet. Is it safe to run with some pain or could I make it worse? Also, I have no arch in my feet, could this have anything to do with the pain? But I have had that issue for years with minimal issues.