I'm 35 year old woman and am on Toprol XL 50mg (generic version) ...

I've been on Toprol XL 50 for 5 years. It has almost completely controlled palpitations, anxiety issues and BP, and has lowered by resting HR by 15 bpm. It helps that I am fairly active. I am not a doctor, but I find it very hard to believe that Toprol is causing these effects you are feeling. There must be something else that is causing your HR to rise and your shoulder to go numb, and you need to figure out what that is, and not presume its your medications. It may be stress over your condition. If you get medical clearance, the #1 thing I'd suggest is to exercise vigorously first thing every morning. It makes a HUGE difference on how you feel the entire day - it does so much more for you than pills alone ever will.