when I review my summary, I've notice that if more than one choice is checked off, it does not give any.
Can you describe what you mean by that?
Do you have a summary report grouped by answer chosen? (if so, these answers where more than one value was selected should appear in your report--probably in its own group, but it can't appear in two places in the same report.)
I assumed that it would be single answer and not multiple choice.
Sounds like you should have used a radio button format with an auto-enter calculation to ensure that only one value was chosen for each question. Either that or each value chosen should have been a different record linked to the same question to begin with.
And that leads us to the solution you may have to employ here as a "fix" for the surveys already completed:
Use a script that finds all records where there is more than one value selected as a response and then loops through these values on each record, generating additional response records so that each record is one value selected for one specific question.