This is a nerve-wracking problem for most parents at some point with at least one of their children. A neighbor child couldn't be convinced to eat a single vegetable for about three years, and only one or two types of fruit. On the advice of a pediatric nutritionist, his parents backed off completely on pushing foods at him, and quietly but visibly enjoyed their own more varied diets at every meal. In a matter of months he was asking to try their some of their foods, and by the time he was six, he would independently order salads for lunch or dinner in a restaurant.
I have known generations of parents with similar experiences. Once they stopped urging/forcing food at their children, the kids had a new freedom to become curious about what they were missing. To M., that indicates that a battle of wills is at the root of their food rejections. Your own story of childhood food preferences is telling. You simply can not get over some of your dislikes. Totally normal – not an indication that there's anything wrong with you or your food preferences.
There are children who have trouble swallowing or have a strong gag reflex, which sounds like the case with your child. There are many, many kids who find certain textures revolting and many flavors off-putting, which also sounds like your son. All of us have noticed that when we feel tense or upset, appetite disappears, so it's important to keep table time relaxed and happy. And it's also SO common that it's normal that toddlers, even those who acquired a variety of foods early on, to withdraw and eat only from a very narrow selection of foods. Some researchers believe this is nature's way of protecting curious kids from poisoning themselves on attractive berries or other stuff they find lying around.
These challenges, which he certainly didn't ask to be burdened with, have probably made your little guy's attraction to food pretty sketchy. Trying to force him past those difficulties is not likely to help, but rather to make him even more resistant. And there are studies showing that too much attempted parental control over food can result in dangerous eating disorders later in life. Food remains a battlefield, but it has become a less conscious and controllable process for the child. I'd want to do some more research of my own if I were in your position. For example, when I google "causes, eating disorders," the very first scholarly essay, heavily footnoted, states that eating-disordered families are "enmeshed, intrusive, and negating of the patient's emotions needs, or overly concerned with parenting."
Of course, from a concerned parents' perspective, "good parenting" can seem to require intensive interventions. But from the child's perspective, he may experience this as leaving him too little space to choose according to his needs, which are emotional as well as physical.
As incomplete as it seems to you, your son's food choices probably represent a fairly balanced selection of foods. Will he eat a chewable multivitamin? If so, I think I'd take a few deep breaths, trust that my son will eventually want to try new foods, and be sure that what he does eat now is as nutritious and high-quality as possible – real foods and not processed ones. I'd also suggest letting him graze – putting out a small bowl of attractively arranged veggies, fruits, nut butter, yogurt for dipping, small squares of omelet, a whole-grain cracker. In other words, a small variety of appealing foods that he is NOT required to eat, but they are available if he wants to try.
Keep in mind that his stomach is only as big as his fist, and some days toddlers seem to have no appetite at all, and he doesn't really need much food right now. I'll bet he'll very gradually forget this struggle when he becomes convinced you have stopped trying to "make" him. Usually by late toddlerhood, a child does start voluntarily expanding his food choices. But they won't if food has become a symbol of personal autonomy and control.