[Grammar] have been having

[wowpetr]

I have read this thread https://www.usingenglish.com/forum/ask-teacher/32213-have-had-vs-have-been-having-headache.html
there is a sentence "I have been having headaches for a year."

but according to Product Groups - English Grammar in Use Online



We cannot use continuous forms for this. Who is right?

 

[5jj]

BobK is right.

 

[wowpetr]

Is "I'm having a headache" correct or only "I'm having headaches"?

 

[bhaisahab]

Is "I'm having a headache" correct or only "I'm having headaches"?

Only the second is correct in BrE.