I tried finding information about how exactly soft body physics is computed from surface mesh or just a group of vertices, but I couldn't find any. How can I get some information about this? For example, does Blender generate a volumetric mesh from the original 2D mesh? Or is there something like "centroid" of vertices calculated in each time step to determine the strain of deformation for every other vertices in the object? And similar other questions.
If you are familiar with C++ you can find the blender source code on github. The code for softbody physics starts in softbody.c
The comment at line 908 is probably the best place to start.