Can't edit or do anything with my file

I've been trying to create some artwork on illustrator for a college project, it works fine, I save it, open it and can't seem to paint/draw or even erase anything in my project. I've had this problem before, don't know what it's called and I can't find the solution anywhere. I am sure someone here might've had the same problem and could give me a few pointers, but I would very much appreciate help as soon as possible so I have plenty of time to finish this for college.

For those curious, it's not a masking layer or locked layer issue, it's something else but I'm not sure what.