about a week ago i had a huge knot in my back, between my shoulder blades. my husband kept trying to work out the knot for my and i was using ice packs to help with the throbbing pain. the pain was shooting all the way down to my right elbow. well the area under my right arm, my armpit and upper chest starting to feel completely numb, the skin has stayed numb for several days. a couple days ago i noticed a red bump above the skin where the knot had originally started. its not filled with fluid, has an itchy but really sore feel. my husband keeps trying to see if it has bite marks on it- but its hard to tell. now my numb skin under my arm, my armpit and top of my chest has an itchy but painful rash- skin otherwise still numb. the red bump on my back now looks more like a welt and it s really sore. What could it be? Stress? Bite? why would it make everything numb then a rash? Please help!