The problem regarding my grades [marks] comes to an end.
In my opinion, your sentence means : I have no more problems regarding/with my marks [ at school]- the speaker wants to state the fact that the quality of his learning is improving and so, he gets higher marks [as a consequence of his efforts in studying harder]
However, I would like to see some experts` advice.
grade - means "mark" [among other meanings]-that indicates the relative quality of a student`s work in a course, assignment ,examination, etc.
grades[ pl.] - elementary school:
e.g. I have been teaching in the grades since 1998.
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