Questions & Answers about Kiedy boli mnie łokieć, nie mogę długo pisać.
Because Polish uses the pattern coś boli kogoś = something hurts someone.
In this sentence:
- łokieć = the elbow
- boli = hurts
- mnie = me
So the literal structure is My elbow hurts me.
That is why the verb is boli: it agrees with łokieć, which is third person singular.
Because mnie is the object form of ja.
With boleć, the person who feels the pain is usually expressed as the object:
- boli mnie głowa = my head hurts
- boli mnie ręka = my arm/hand hurts
- boli mnie łokieć = my elbow hurts
So mnie is used because it means me, not I.