I'm an expert (actually have my own business- look at the business listng here lol)
& yes talk w/ your doctor to rule out pyloric stenosis
but if it's not that & there's no pain involved, there isn't really any medication for excessive spit up...
a food journal is an excellent idea!
it takes 3-4hrs for what you eat to make its way to your breastmilk, so if he is reacting to a protein (that's what they react to, proteins, it's rare to have actual lactose intolerance as a baby but that's a whole other post, lol) you can then try & figure it out...
HTH
~L.