When you have problems with relations with other people...

[Firewind]

It has been my experience, too, that these feelings of nausea originate in the solarplexus / 3rd chakra.
In my case, it is dark/confused energies which I have in that area (probably past lives-related ... it's pretty weird stuff anyway) going into resonance with something that's outside of myself.

Energies relating to hierarchy, authority, dominance/submission etc. give me nausea (so basically it's about assigning unequal "worth" to different entities, including oneself).

Contemplating the "metaphysical nature of one's stomach" (one might, for example, look into Chinese medicine) seems to help to "digest" these energies.

Also, "bringing light into the darkness" seems to be pretty important - at least in my case, the duality of light and "no light" is very much present in the solarplexus area, and exposure to a certain amount of sunlight helps a little with this.

Interestingly, I am noticing a strong resonance between smoking tobacco and blockages of the third chakra, though I haven't really figured out what this is about...