What Causes Rash On Wrist, Behind Ears And Under Armpit?

Hi.I have started with a small rash on my right wrist,it is not very itchy,and did not bother me.I have been having a bit of a sore throat,but better now.I do still have a blocked nose,with a bit of difficulty breathing,also a bit of a headache now and then and fatigue,just like the flu.Today I have notice that I have a bit of a rash behind my right ear and just under my arm pit area,also the right side.Is it anything serious?