Raiden

Bottom bracket. It's worn internally, or loose or installed dry. Im assuming you have a square taper bottom bracket- Buy yourself a square taper puller and splined bb tool, they're good investments. Read up on bb install/removal procedures, it's possible to damage your frame if youre sloppy or mess with your chainline if you get the wrong part. The parts are relatively cheap and will save you a lot of money in shop labor once you learn how to use them.

Also, those are fairly entry level pedals, they'll probably ride just fine for some time, but it'll be normal for some noise or gravelly feeling.