[OS X TeX] citation in text fail to appear as expected

[konstantinos vasilakos]

Dear all I have a problem which I can't find the solution for a couple of hours now, which if I will manage it will mean that I have made the half of the whole work.
I want to make a citation inside my text, so I use the \cite[the problem lies here] {cite key}
But this will just add the citation  as part of rest text.
Thank you
\K.