Why am i spitting up blood and phlegm if i only have sore throat?

See a doctor: Sore throat and bleeding needs to be seen by a doctor. An otolaryngologist (ENT) can easily look in your throat to see where it might be coming from. The flexible scope is very easy to tolerate with local anesthetic. I have had it done many times to teach med students how to do it. It is usually nothing serious--bronchitis, nose bleed, etc. But you need to be sure.