Question

I missed something in the last lessons on conceptual analysis of a loan:
Does the lender have a right to receive back the money (which now is not his) from the borrower, or is it only a debt upon the borrower to repay it? In other words, does corresponding to the borrower’s debt to “return the money” there stand a right of the lender to receive it? It seems to me that the answer is no, because the Torah cannot say to the borrower that in the Sabbatical year you are not obligated to “return the money”, because there still is even though he will no longer have a debt the lender still has a right and that is his territory?! Rather, apparently he has no right. But if it is only a debt and not a right, why are the laws of loans found in Choshen Mishpat and not in Yoreh De’ah?