Do you know of any utilities that can convert an *.obj file back to its original code (*.cpp/*.c)?
The simple answer is that there is no hope of such a utility.
The problem is that the C compiler converts the C language statements to machine code. Converting them back would be a monumental task, and the odds that the result would be what you started with are virtually impossible.
Further, unless your object files contain all module symbols (such as when you compile with debugging information), there would be no way for the utility to determine what any of the variable names should be.