I worked in Clarks shoes in the kids section for a year and a half so I know all about narrow feet lol.
Have you ever had your feet measured properly? If not, I recommend you go into somewhere like Clarks where they can measure both the length and the width.
The thing is, most ladies shoes do come up quite narrow - well in the proper shoe shops, like Clarks, they do anyway. They come up normally at a D width, whereas the narrowest kid fitting is an E width, so the ladies average width is smaller than the narrowest kid fitting!
If you go to get measured, they can usually tell you what the 'problem' is with your feet and why heels aren't fitting. I'd guess that the width of your feet isn't even the only problem - you may have a low instep (ie. that bone on the top of your foot may be really shallow, so your foot isn't essentially high enough to grip the shoes) or your ankle may be really narrow so its not gripping the shoe at the back. Heel grips may help with this.
Woah essay. Good luck!