Yes, I have used poor form in the past but never injured this way. I have problem with sleeping on them. Either if I sleep with shoulder over head of on the side, they end up causing pain. Anyway I have fixed my form, and have felt improvement.
While my shoulders heal though, using the space between the bar and chest has helped greatly.
Thanks everyone, I will look into that shoulder saver pad. and I have seen that slingshot thing before also.