Most cases of those painful heels, sore feet and low backache in young can easily be traced back to use of such extreme fashionable footwear. If God wanted us to walk on those high heels, he wouldn't have given us such beautiful feet.
Coming to low backache, life starts getting a bit more complex. Low backache could be due to something as benign as a strain/sprain or life may start getting a bit more complex with degeneration of intervertebral discs and facet joints or confusing with undetected pelvic tumours/inflammatory pathologies causing secondary low backache.