Hi Doctor My Baby Was Born On 27 July..i Coulnt

Hi doctor my baby was born on 27 july..i coulnt breast feed him till he was 8 days old bt he didnt like breast feeding n would just go to sleep after we got discharge on 11th day i started giving him lactogen n since then he feeds lactogen n only little breast milk...but now more frequently he opens his mouth n makes a sound like something is coming out forcefully like people vomit after getting too drunk bt he never vomits n this only happens after o while bottle feeding lactogen....do i need to change to another milk o is he just chocking....is it normal ?