It's a cyclamen. Hard to tell flower size from the photo, but I'm guessing that it's one of the florist types.
A quick Goggle search gave me this page that talks about growing them indoors.
The florist types have larger blossoms. I'm most used to seeing them in stores around Christmas. Here in Seattle, we have hardy cyclamen that bloom in spring or fall depending on the species.
It's not a Begonia, it's a Cyclamen, cyclamen persicum to be precise. It likes bright light, but not direct sunlight, so a north facing windowsill is ideal. Prefers cooler temperatures (50-60deg F) and damp soil - it's better to water into an outer container and let the plant soak it up to avoid soaking the tuber or corm too much, which is usually sitting just proud of the soil in the pot. Best to use soft water if possible, and mist occasionally because it prefers higher humidity.
It currently looks as if it needs more water and certainly more daylight, but it may be deciding to go into 'rest' mode, which they do need to do for a while, depends how long it's been in full leaf whether that's the case or not.