Best for me is buttocks or glutes.. The absolute worst is chest! I got hurt at work not to long ago and was out about 1 month. My right side was all bruised and swelled up. My right breast was huge, doc had to withdraw about 70ccs of blood from it. Worst pain I ever felt from a needle.. Stuck a 20g in there 7x. It felt 100x better when he was done..