[misc] Head stinks even after daily showering and shampoo

I was laying down with my bf and he told me that my head smelled bad and he was pretty serious about it. I am shocked because I never thought this could be possible given I wash my hair everyday (even shampoo sometimes daily).

Please help me out atleast understand what I can do to counter this because this kind of shattered my self esteem for a bit.

Thanks in advance!