Moving from assembly to C
Microchip has several free Compilers that are paired with the free MPLABX IDE (Integrated Development Environment).  You can get a compiler for 8, 16 and 32-bit microcontrollers.

The difference between the free versions and the paid ones is the latter optimize the code, making the finished binary much smaller.  I've seen size of the binary shrink by half.

One feature of the IDE is that you can open a disassembly window which will show you your C program followed bu the code that it generated.  The following is from a PIC32 program (32-bit MIPS assembly):