hello all ,a friend of mine was explaining this situation to me so i thought i would ask those with more experience their opinion .. he was preparing two shots first shot 1 ml test prop/ .75 ml npp ..second shot 1 ml test cyp .house was cold so he ran the prepared pins under hot water for apx. 5 min the prop and npp went smoothly into glute .. second shot into delt test cyp was extremly hard to push plunger in .. almost as if something was blocking the flow .. this wasnt his first shot in either spot and this had never occured previously . so after all that the question is what would make a shot so hard to push in .. if anyone has had this experience .. also if this were to happen again what should he do .thanks