Livvy had reflux and my non medical understanding is that it is something he will grow out of but it may take time.
It is only the milk coming back up and giving him that horrible feeling in his chest.
obviously for livvy with bad lungs the problem was wet lungs but i believe it is not usually a problem. (livvy had diaretics to make her wee so she didnt keep excess fluid on board)
it causes different issues for diffrent babies and the hospital will check if Aiden needs anti-biotics or anything.
I would see your gp and get more stuff until you have been to the hospital.
Try not to worry but i know this is hard.
love cheryl xx
