What Causes Difficulty In Swallowing?

I had a very traumatic gastroscopy three weeks ago - done under sedation when I was told I should always have a full anaesthetic. I was conscious of the 3/4 person team panicing and shouiing instructions to oneanother. I couldn't breathe, afterwards my pillow was soakede in blood and mucus. Next morning had horrendous rash all over my face throat and upper chest - small pin-prick size brown/red spots. Tthree weeks later still having swallowing and choaking episodes, pain at front of ribs and back of ribs, sore kneck and occasionally swollen glands.