I have partial-power-loss as a result of a heater and christmas tree plugged in the same line in my home. The problem I 'm having is that each outlet that was affected still has 115V on ether side and ground , is this the result of a hot attaching itself to ground somewhere in my wall? And how can I test this therory without ripping the wall apart.

You may have lost the Neutral.
You should have 120 volts between Hot(small prong) and Neutral(Large prong), you should also have 120 volts between Hot and Ground.
You should have zero volts between Ground and Neutral.

A neutral on that circuit has opened and power is going through a load to make neutral live, Unplug everything on that circuit, turn off all lights, this should remove the voltage off the neutral.
Then I would turn off THAT breaker and see what circuits went out, check those boxes, could be last good or first bad receptacle.
If able to work safely in panel, I woul see what circuits exit the panel with the circuit you are working on, the one with the breaker off.
May be in one of those boxes.