4 month old won't nurse or latch correctly

[@llli*liz2004hb]

I'm so upset about this situation. My 4 month old son (who is a twin) has started really fighting feeding in general, but for some reason over the past few days has decided not to latch on anymore. He has unfortunately been getting bottles of formula and breastmilk since birth for a number of reasons, but up until a few days ago this has not been an issue. It seems like he is in pain when he eats. Be it bottle or breast, he arches his back and cries and will only eat a little bit at a time. He has a number of health issues going on, but they shouldn't be affecting his eating. This is new. Is there anyway to get him back on the breast and latching correctly? I tried a nipple shield for the past few days and it has caused what feels like the onset of mastitis, not to mention isn't helping him have more interest. His twin brother is latching and eating perfectly and is exclusively breast fed without any problems. I'm sick inside of the idea of him not breastfeeding. Need help on this issue asap!

[@llli*mercystreet]

I am admittedly not very knowledgeable about breastfeeding multiples, so I'm just tossing an idea out there... but the thing that stands out for me in your post is "Be it bottle or breast, he arches his back and cries and will only eat a little bit at a time." This makes me wonder if the problem might not be latching, or the bottle/formula v. the breast ... but maybe something else. Have you talked to your pedi about the possibility of reflux? A friend of mine's baby had acid reflux and reacted *exactly* like that.