Yes, there is a chance that the wall could be a bearing wall.
You can determine if it’s a bearing wall by verifying if 1) the wall is near the middle of the house, 2) has roof joists resting on it, 3) has a beam or concrete footing under it, 4) has plywood, OSB board or double gypsum board on either side of the wall.
1) If the wall is near the middle of the house there is a strong likelihood that it is a bearing wall. Because you mentioned that your roof is flat, there is a strong likelihood that roof trusses that span the entire width of the house were not used, but you’ll need to verify the other items I’ve listed.
2) You’ll need to look in the attic to see if any joists rest on the wall. (Flat roofs will probably rest at mid-span across the roof.)
3) If you can’t get in the attic, you may be able to get in the crawl space and see a beam or concrete footing under the wall. If so, that is a strong indication that it’s a bearing wall.
4) If you live in a high wind area or a seismically active area, the wall may provide lateral bracing. If plywood, OSB board or 2 layers of gypsum board on either side of the wall, then the wall could be a structural wall. (The wall would need to extend up to the roof to be structural.)