A lot of people say they get good results from botox. Just make sure y ou have a very experienced doctor do it.
I tried botox for my shoulder spasms but unfortunately I discovered I'm one of the few that has an adverse reaction to it and it made my pain much, much worse. And, since the shots are to last for 3 months (or more), the increased pain hung around for those 3 months

But it's one of those things that you don't know how your body is going to react to it until you try it.
That's why I got referred to the new dr. I have now who just does the guided imagery shots into my shoulders with simple steroids/lidocaine. It does help but only for about 3 months but no adverse reactions to this medicine other than insomnia for the first 4 nights or so.
I hope that if you do decide to try botox that you get a very qualified doctor and that you get the pain relief you are looking for! Hugs!!