Maybe you have this figured out already, but just in case, here is your answer.
For physicians you need to get your MBBS assessed through the MCC. You can also get your MD assessed too.
As a pathology resident, you will be in the NOC category 3112 and your job title will be 'physician resident'. This is considered as work experience and you can get a letter indicating the date of joining the program, weekly duties with hours, and salary (stipend). If you are also working as a GP, you use the same NOC category. In this case, you will also include a letter indicating your work hours, duties, and salary.
I hope this helps. All the best!