Well of course grief and loss go hand in hand
@Abstract , of course grief has physiological effects but it's not an illness specific. And without a cognitive component there is no grief- if there's no perception of loss there is little or no grief. It's unique to each person, one could say their heart breaks, another it's a kick to the guts, another a black void of nothingness, another they are going to explode, another the bottom has fallen out. It's like being a giant (human) potato, being peeled. A lot of people run to doctors thinking they are ill, and because of how bad they feel, only to find nothing definitive. Whatever it is, and however you feel, including what you experience physically, one thing is you won't be the same person after. Maybe not worse, maybe not better, but never the same. You can't be.
Have you ever equated your emotions to your body? It's quite simple, really. For example, you mention solar plexus, well, if you think, "I feel like I have been knifed in my stomach", then you ask yourself what in my life feels like a knife to the stomach, or you would describe that way? And you will know if you are grieving, and what you are grieving if so. Such as, ~'my son's words cut like a knife in to my stomach'. And if you identify it accurately, the pain will diminish, if it doesn't have a definitive physical cause. So that could be hurt, or it could be grief (the relationship to your son +/or his childhood will never have a do-over). Or grieving your parenting skills were affected or influenced by your own childhood. Etc. Not quite as simple as one might first guess. You might grieve your losses, you might grieve other's too. I think it was
@Justmehere in the thread you mentioned that said along the lines of grief is reality where something else should have been.