Like "I have not had that happen, and I have been doing insulin for a very long time,(juvenile). You may have injected it wrong, different angle? Do you reuse needles, if so then you could be getting an infection at the site. Did it hurt immediately, if so then doubtful an infection. I'm also assuming you are rotating your injection sites? Try putting ice on it for swelling if there is any, if not then apply heat for short time periods and that should help the pain. You dr should have a 24 hr service, so call and leave your info and a dr or nurse will call you back quickly. At least you'll have a better answer and not worry. I hope this helps some. Good luck and let us know what happens:)"