Sounds like a window motor, which requires removing door panel, checking to be sure it's the motor and not the switch that's bad and replacing it. I've done it on other cars but not an mdx. So others can come in on specifics
Check the fuse (look up which one in your owner's manual). But most likely it's the window motor/regulator. The good news is, they're not expensive, and they're not that tough to replace. I've only done the rear but the front shouldn't be much more difficult.