Is this senternce grammatical? The context is as follows: a patient comes to the doctor's and can't explain what is wrong with him.
If I were a native speaker of English, I would never shut up. :-)
I would use "The funny thing is that I can't really explain to you what's wrong".
Even though it is the doctor who will determine what is actually wrong, we tend to use the phrase ourselves to mean that we don't feel "right" (ie completely healthy).
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.