Is the regurgitation small amount (e.g. 1 mouthful) or vomiting the whole feed?
My breastfed boy regurgitated small amounts from 4 month old. Sometimes, it's a sourish-smelling liquid too. Could be mild reflux.
I burp and hold him upright after a feed for about 15-20 minutes. If putting baby down, use a slightly inclined surface (about 30 degrees) to ease the reflux.