Freezing cold cabin housing just under a window I flew on a Boeing 737 plane yesterday and was sitting next to 2 windows. When I tried to rest my arm on the inner housing of the cabin during the flight, I noticed that the inner cabin housing just below one of the two windows was very cold. It was almost like touching a surface in your freezer. I was under the impression that it is not a common thing and that it could only result from outside air being in contact with the inner cabin housing which I believe is not supposed to happen. 

I spoke to a flight attendant about it and he came check the window, but I feel like his feeling all in all was that I was worried for nothing, and I’m not sure he actually shared the information with anyone - and he did not thank me in anyway for reporting a potential issue. 

I’m curious of anyone views on this issue. My uneducated guess was that it was maybe not a critical issue now, but a defect that should be known by maintenance teams as it could be tied to a structural issue of the outside window.
It's not a structural problem, and nothing to worry about. The cabin of an airliner is a pressure vessel, the pressure outside of the airplane is far lower,  if there was a leak air would be going out, not in. The air outside is very cold, which makes the skin of the airplane cold, there's insulation between the skin and the cabin fixtures but if that comes off a bit you get cold spots. 

By all means tell the cabin crew so they can log it for the next time the airplane's in for maintenance, it's important for passenger comfort.