You do *NOT* want "1,2,3,4,5" in your database column. PERIOD.
You should *NEVER* store a LIST of values in a single field in a database.
You should store each checkbox in a SEPARATE RECORD, probably in a separate many-to-one table.
You don't show us your DB design. You don't show use your code. There's not much more we can help you with until you share more of your problem.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.