last night i did my 6 shot in the glute. i have always had problems doing it on the left side. last night idid it in the left side but half way in my entire left glute jumped, so i stopped them pushed in it a littls more and it started jumping really fast after that. i pulled it out and shot on the right side. what the hell happen? it never jumped like that before. can someone tell me what i did wrong or why it did it.