Student or Learner
As the title reads, I am not sure whether you can say: "to have a lot at heart", meaning that you have a lot to say. Or is there another phrase for this?
NOT A TEACHER
(1) I believe that you can say:
I have a lot to get off my chest. = I have a lot to tell you, especially negative things
P.S. Because of the word "chest," it might be a good idea for females NOT to use
this idiom. Some immature people might laugh.