Hi There, Since I Was About 18, I Am Now

hi there,

Since I was about 18, I am now 45, I have noticed bloody streaks in my sputum of a morning. today it was red, other days, most days, it is dark brown. I have constant face pressure which my dr suggests is sinus, but an MRI last week revealed no polyps. It is only in the morning and it is not coughed up its just there from what I think might be a post nasal drip. Any thoughts? Best wishes