evidently there was host versus disease and the changing of the blood type was painful.
Ive never heard of pain occurring with changing of blood type. The bone marrow has basically been killed off by chemo (and radiation if used). Honestly, 7 personal years and thousands of posts on the page, I’ve never heard this. Perhaps, your friend misunderstood the dr.
There is/can be pain because of the rapid new cell growth in the bone marrow after the stem cell transplant, but, that’s not from blood type change. I too experience the deep ache. And then 7 years of Neurapathy from the intense chemo for AML and the SCT.