I have Botox every few months. I find that it stings for a short while after, but apart from that it's like any other intra-muscular injection in that the 'tighter' the muscle being injected is, the more sore the actual injection is going to be (and unfortunately I can't relax those muscles to save my life!).

That said, I can convince myself to hold still because I know what improvements will happen. I also found that some positions were better than others in terms of trying to get the muscles to relax just a little bit more.

HTH
Swift