I am here for you with the same story and finally I am getting there! I have the same shoulder pain as well as up into my neck when it is at its worst (hurts to even turn my head). Even when it wasn't at its worst though, I had a stiff neck...24/7! I use heat when it is really bad and it works great, temporarily of course. I have done 15 flushes and between 13 and 14, it has started to ease up. I have more and more instances through the day where even my stiff neck goes away. You'll get there but from what I understand, and I am a testament to it now too, when you have this type of pain there are a lot of stones that need to come out. I have flushed one gazillion at least. BTW I am 37 too. :0)
Kidney cleansing is important too. I found a place that sells everything you need, measured in a bag for Andreas Moritz 's kidney cleanse. presentmoment.com
As for frequency of flushing, you just have to find what works for you. I used to wait 3 weeks because that was working. But the last few I have done two weeks apart and still have success because I think I have finally decongested it and they are rolling out now!
I hope this helps you and please know you are not alone. I never have had painful gallbladder attacks (thankfully) and it took a lot of time and research to figure out this is all connected.