You may have gotten an infection at the injection site. If it doesn't subside soon you'd probably best see your doctor. Another point: I have a doctor's assistant administer mine and if I don't completely relax the muscles at the site of injection I get immediate pain and ongoing pain afterwards for a day or so. I get my shot in my buttocks and make a point of relaxation my gluteus muscles. But of course you cannot do likewise. Good luck.,
Maybe you did hit a nerve. I have never had that happen to where it was so sore I could hardly walk. I have had some mild soreness but nothing like that. If it is an infection it will probably be red around the injection site, swollen, and possibly hot. But if you have any doubt go get it checked out.