It may be worth asking an experienced teacher about your alignment particularly regarding the wrists and hands. Incorrect alignment of hands/wrists/arms can cause discomfort and possibly lead you to believe that the discomfort is due to the hardness of the surface.
A too soft, too padded mat can lead to incorrect wrist/hand alignment and end up causing more harm. A very padded mat can also be unhelpful in standing asanas.
I regularly practice on a wooden floor without a mat and have no problems at all....although it can be slightly uncomfortable if my knees are weight bearing on the floor.....but no issues at all with weight bearing on hands directly on the wood surface.