What could be possible reasons for Atmega-chip and Xbee heating up?

Other Hardware General Electronics
5

giantsfan3:
The heating up is happening on the Atmega chip and the Xbee only. While the part of the PCB around these parts is also heating up slightly, the rest of the PCB and the rest of the parts are cool.

So you are seeing about 40C around the two most active components? Both which are probably rated for at least 85C...