There is NO reason that my walls should be getting cold enough to freeze water.
There is outside air getting to where the ceiling meets the wall. I assume it is on exterior walls. I used to work for a truss design/manufacturing company. Poor insulation job or there is not enough room at the heel of the truss for insulation, it is called an energy heel, it allows for the same amount of insulation on the perimeters as in the center. ......Boring holes through the ceiling would probably reveal the problem or removing soffit. Sorry about the bad news. I am pretty sure.