(1) There is a superfood called (in English) "Job's Tears". It is somewhat annoying that this is the only name we've got for the plant in question, and if people at the health food store don't know what you're talking about, they'll be confused. However, it is high in protein, and it is NOT a legume (and it is gluten-free).
They were eaten in medieval Europe (i.e., they are not an exotic/foreign food) but have dropped out of the modern diet in most of the western world. They continue to be eaten in Asia, but they are a "low status" food there (i.e., not associated with wealth).
This is what they look like before they are boiled (i.e., in their dried-out state, as commonly sold).
The top half of that image shows Job's Tears, in contrast to a type of barley they're often confused with.
When they're boiled sufficiently, they're soft, puffy and white. They are used in some soups, but if you're eating this as a source of proetin, you'll want to eat whole bowls of it (as if it were rice).
(2) In terms of self-diagnosis, there's a huge leap of inference being made in what's causing your condition. In your situation, I would not be comfortable assuming that the link to legumes was one of causation rather than correlation.
There is absolutely no way
that the same health effect would be caused by foods as diverse as lentils and eggs. So, you've already started to produce evidence that contradicts your own initial theory.