I've driven myself insane trying to work this one out.
Some ideas of mine, but not sure if they're correct:
I don't feel 'safe' in my body. It feels constantly threatened, by itself, not the outside world, just itself.
I used to have an eating disorder, and this has a similar internal dialogue - perfectionist tendencies and a loathing of uncertainty.
Had an illness at age 8 that made me see my body as vulnerable and I hated it. (got well very quick so no lasting damage).
Have experienced a trauma in childhood.
I think HA can lie dormant for years. I had it in my early twenties, lasted a few years then only resurfaced in my late thirties.
I believe I am 'living wrong'.
Can't explain it any better than that.
There is too much 'space' in my mind that allows me to ruminate on diseases, to feel every tiny sensation. This space needs to be filled with something else, another mental occupation that does NOT involve negativity or obsession.
At the time my HA returned, I was in a dying relationship, hated my home, felt lonely, was unemployed and felt ugly.
Many of those issues are now fixed, but the HA will not budge!
It's like mental glue.
Lots of triggers. No cure