One room in my new house smells... Kinda musty?

I bought a new house. It was a flip, but the guy who did it did a really good job. Even had the inspector comment on all of the things that the flipper did to correct issues that were present before the house for flipped. The foundation was fine, the house had a leak at one point, but it was corrected and we could see the work showing that it was corrected. The room where that leak happened smells fine. One of the bed rooms that has a wall that has the garage on the other side of it has a slightly musty smell. It's not super intense, but it's noticeable. I can't seem to find where it would be coming from. No signs of moisture or mold. The floor doesn't seem to be in rough shape, and I've even sniffed along the floor with no luck. I'm wondering if the garagey smell is just seeping into the room, but I'm also worried about mold or mildew being behind the drywall. I also don't want to start an expensive project after just buying a home. I just dropped $46,000 into it! Anyone have any thoughts. Should I be concerned or just leave it be? I'm a first time home owner and have been here a week.