This may be a result of the way that you were added to the Canvas course.
In this Canvas guide, How do I add users to a course? under the Select User Details sub-heading, see the image and point 3: there is an option upon adding users to a course that limits their interaction to users only in the section(s) they are part of.
Depending on the way your Instructor's permissions are set-up at your institution, they may be able to amend this for you.
One way of doing this is under your user profile, see: How do I view a user's profile in a course as an instructor?
Under View Memberships, there is a screenshot showing 'Privileges', where an instructor can choose to 'let this user see all course users'. If your Instructor selects this for you, you won't be limited to the sections you can view and interact with.
Alternatively, your instructor may want to only allow you to see/interact with certain sections. In which case they can just add you to the additional section(s) to allow you to access it: How do I edit sections for an enrollment in a course?
Hopefully one of these options proves useful!
I have been reviewing older questions here in the Canvas Community, and I happened to come across your question. I wanted to check in with you because I noticed that we have not heard back from you since you first posted your question on October 18, 2018. I see that @jeremy_stevens was able to provide you with some feedback later that evening. Have you had an opportunity to review Jeremy's response? If so, has it helped to answer your question? Or, are you still looking for some help from members of the Community with your question? If you feel that Jeremy's feedback has helped to answer your question, please feel free to click the "Mark Correct" button next to his response. However, if you are still looking for some help with your question, please return to this topic to post an update below so that someone from the Community might be able to help you out. For the time being, I am going to mark your question as "Assumed Answered" because we haven't heard back from you in over five months and because there hasn't been any new activity in this topic for the same amount of time. However, that won't keep you or others from posting additional questions and/or comments below that are related to this topic. I hope that's alright with you, Evan. Looking forward to hearing back from you soon.