Baby constipated started solids

AL

Ped warned me that baby would probably become constipated after starting solids but never told me what to do for it- and mommy brain didn’t have me ask!

What tricks can help him? He was up ALL night straining and crying and every single diaper today has had 1 ball of stool. I’m dreading him being up again tonight- momma is tired and I feel soooo bad!