From what you've said, at this point, it doesn't sound like the cracks are that bad so they are not likely to affect the building structure. It also depends how the floor was put in to begin with - sometimes the walls are built first and then the concrete is poured after and is independent of the walls.
There's two things here on the cracks: 1) if the cracks are the result of ground heaving, then a little patch wouldn't do - you'd have to do a serious rehab on the floor to make them go away (time and money!); or, 2) the ground may have shifted as much as it is going to do and, if so, the cracks will not get any worse so they could be left alone. Probably the best thing to do for the time being is monitor the situation for awhile (time wise, we're talking months not days) to see if there is change and make up an action plan then.