Assalaamu alaykum. Sometimes, when we are surprised or hurt or find something funny, we say 'O my mother' or 'O dad'. Is there any sin on us for this?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

It is most likely that the person who says 'O mother' or 'O father' and the like, when he is surprised, does not intend to seek help from his mother or his father, but these two words come out of him spontaneously because of the predominance of this custom, so it is not forbidden to say these words.

However, a Muslim should accustom his tongue to uttering Islamic words that are said in such situations; so he expresses his surprise by saying 'Subhaan Allah' (glory to Allah); he expresses pain by saying 'Inna lillah wa inna ilayhi raaji'oon' (To Allah we belong and to Him we shall return); he rejoices by saying 'Al-hamdulillah allathy bini'matihi tatimmu as-saalihaat' (Praise be to Allah by Whose grace good deeds are done); and he bears hardship by saying 'La hawla wa la quwwata illa billah' (There is no might nor power but by Allah) and other Islamic Athkaar (plural of Thikr [expressions or remembrance of Allah]) and supplications.

Allah knows best.