First of all, 'string with commas' should not have been stored in the same column, that is a big mistake, that is a violation of "first normal form" rule in relational database design. There is a good article on this
11 important database designing rules which I follow[
^]. You can ask google for more information on relational database design and related matters.
To answer your question: after retrieving the 'string with commas' from your database:
To separate the string,, adapt this
Split[
^]
To display items in radiobuttonlist, check this out
RadioButtonList[
^]