… todo a mis amigas miraflorinas, les daba mala espina

… todo a mis amigas miraflorinas, les daba mala espina que Lucy y Lily no nos …- what is the best translation for "les daba mala espina"Ç

something like: they had serious misgivings

Gracias

Actually it is more like

he/she made them feel uneasy les daba mala espina
they made them feel uneasy les daban mala espina

I am not entirely sure if got the pronouns right but dar mala espina means to make someone feel uneasy

I guess you can translate it both ways. In case it helps to build up an intuition about the use of this expression, I think that “Esto me da mala espina” would be an adequate rendering of this well-known cliché:

Thanks Francisco, again. I was curious about why “espina” would be used in this expression if it means “thorn” or “splinter”. It may be related to something being a “thorn in the side”?

Yes, I Do think it’s related. This post by writer Amando De Miguel also gives a similar explanation: Diario online con noticias de última hora y opinión
A “espina” is a thorn, yes. Also a fish bone. Splinter, on the other hand, would be an “astilla”