In May, I had a crown replaced as it had become slightly loose and led
to further decay of the tooth underneath.  After the replacement, I
noticed a sharp pain whenever I would floss.  This is the 3rd to last
tooth in upper right back.  Went back after two weeks and had a x-ray
done.  Dentist said everything looked fine. Told me to give it some
time and come back if it still bothered me.

I've been dealing with a possible sinus infecton for the last two
months.  And now I wonder if there is a correlation between the tooth
and the sinus infection.  When I floss the tooth, there is still some
pain, but by the smell test, there doesn't seem to be any decay.  I'm
suffering from occassional dull pain on both of my upper sides.
Thought it was the sinuses annoying the teeth, but wonder if it's the
other way around.  But I'm not suffering any particular pain with this
tooth alone.

Will see the dentist soon and wanted to bring this up. Could he have
done something with the tooth that would have aggravated my sinuses?
Does it sound plausible?