I have normal width feet with narrow heels that also don't have a pronounced "bump" on the back. Shoes, especially anything slip-on with a low vamp usually slip right off or cut my achilles tendons terribly.
I found a pair of slip-on sneaks that were unusually narrow in the heel and added a pair of gel heel cups that cover the back of the foot along with socks and am comfy as can be today.
Just thought I would put it out there, since nothing has worked in the past for me especially not the straight heel risers, other inserts or those little get strips. I also have some ninja sox on order and will review those as well.
I literally have not had a pair of shoes that doesn't lace on or isn't a bootie in 10 years.