my mother is cosigner on a mortgage in pa. and my boyfriend and i live in t

If both of you want to be considered as the borrowers of the mortgage, then the lender will ask you to add your boyfriend to the property deed.

You will have to refinance the mortgage in order to remove your mother's name from the property deed. You should contact your lender for the same. If you want your boyfriend to co-sign for the loan, then you will have to add his name to the property deed.