I am entering information from a 1099 sa. There are two line items and each have a gross distribution amount (box 1). Do I add them together?

Yes, you can.  If the line items are from the same payer, for the same taxpayer, and all the other boxes on the form match for both line items, there is no harm in adding them together and reporting a single Form 1099-SA. 

If there is any difference at all with the other items reported on the Form 1099-SA, enter it as two separate forms.