Hello I hail from Portland, OR and have recently found this plant growing as a weed. I know most of the weeds in my yard but haven't come across this plant before and have been waiting for the flowers to appear for an ID.

They are 4-petaled flowers with pubescent stalks. Opposite leaf arrangement. Serrated, reniform leaves with petiole.

I suspect it might be some kind of Phlox but what kind? The flowers look an awful lot like "Dame's Rocket" but the leaves are opposite on this mystery plant whereas Dame's Rocket is alternately leaved. Can anyone help me track down this ID?

I can take more pictures by request and might just go take some more for fun anyways.