Every now and then i wake up with a headache, i took tylenol (acetaminophen) i still have a headache that always on the side of my head. could this be from coumadin?

Doesn't seem: Very likely if the ha pattern that is common for you. Crescendo severe ha in a new pattern would be of more concern relative to Coumadin (warfarin) complications.

It's possible: Headaches could have one of many possible causes. A coumadin-related headache would be very worrisome since it could be caused by a bleed in your head. The higher your inr (coumadin (warfarin) blood test), the greater the risk of a bleed if you hit your head. High blood pressure and migraine are two other causes and the list of others is long. Get your inr and BP checked; tell your md of your headaches.