Hi, I have been using crack cocaine recently and I m starting to have complications. When I take a hit no matter how small my left arm immediately stiffens then tingles, I a feeling of a lot of pressure in my head, a spot in my chest on the last side swells up my throat tightens especially on the left side and its hard to breathe, I also feel tight in my lower back. I know it s wrong to use, I need to know whether these symptoms are life threatening or not.