Has it been ongoing or just recently? DS went thru a bottle aversion a few times --we'd find out that he either had an ear infection, was constipated or was getting a tooth in. The other issue was that he didn't like textures of certain things -- ground meat, toast, applesauce -- made him gag like he had a hairball. He preferred babyfood pears or bananas.
We started feeding him solids around 6 months -- and even then there were certain things we knew he liked and things he hated -- loved baby food jars of oatmeal with pears -- hated rice cereal. Loved yogurt. Loved stage 2 mac & cheese. At daycare they ground up what the big kids were eating very finely and he'd eat that, unless there was the teeniest, tiniest pea in it -- he could sense it a mile away.