The title "It's all in your Head" looks like she's bursting onto the scene unasked to make a claim or assertion. Which in fact she is.
The change to "Is it all in your head?" could just be a device to make it look like somebody asked for her opinion, thus making it more legitimate for her to look over the rim of her glasses and start spewing nonsense.
It's a bit like when someone starts a sentence with "people often ask me ..." before going on to give you their long boring opinion on something you weren't the slightest bit interested in. Yeah, sure people often ask you. You wish.
The change to "Is it all in your head?" could just be a device to make it look like somebody asked for her opinion, thus making it more legitimate for her to look over the rim of her glasses and start spewing nonsense.
It's a bit like when someone starts a sentence with "people often ask me ..." before going on to give you their long boring opinion on something you weren't the slightest bit interested in. Yeah, sure people often ask you. You wish.