A thorn in your side is a small problem, not a serious one.

“你的眼中钉”是个小问题，不是大问题。

A friend who always borrows money from you could become a thorn in your side.

一个总是向你借钱的朋友可能会成为你的眼中钉。

We hope that your English studies have not become a thorn in your side.

我们希望你的英语学习没有成为你的眼中钉。

So, a thorn in your side is something that hurts you.

所以，你身边的刺就是伤害你的东西。

All in all, pain seems to have a pretty important purpose even if can sometimes be a thorn in your side.

总而言之， 痛苦似乎有一个非常重要的目的， 即使有时会成为你的眼中钉。

" A thorn in your side" is something that is very annoying, very unpleasant, something that is painful and won't go away.

” 不愉快的，痛苦的，不会消失的东西。