Sore throat, yellow phlegm, rash, bruising, nerve pain, muscle pain, itchy skin, tingling feet, headache. rash dissapears 20 minutes. cancer? worried.

Take a deep breath: Relax... It does not sound like cancer. Those are a lot of symptoms though. It is most likely a viral infection, like the "flu", but it could be something else, so you should go see a doctor and get a proper exam.

Unclear: Cancer would not be the first thing that i would think of. With all of these symptoms, you should see your friendly primary care physician and try to find the cause.