pain after a injections??

i had a filling that fell out with no pain went to get replaced no problems then after the numbness went the pain was terrible,thought would leave it a day for it to settle then couldnt cope so went back and the dentist said the metal filling was sat on the nerve so took it out and said would put in a medicated filling to treat the nerve so as the dentist went to numb the area it took 3 injections for me not to feel anything put the filling back in,then the next day had bit of pain but not as bad then my ear started to hurt and thought would go doctors she couldnt see anything but gave me antibiotics just incase,was telling a friend and she said maybe its a muscle where the injection has been as had 4 injections in the same area in the past 2wks? when i open my mouth at the back it looks bruised could this be the case of a bruise or does the tooth need to come out?