@Anxiety121 You'll be ok! We all were scared about our referrals, but got through or will get through them.
Regarding the pains, I tend to agree with Emls and Carys in that it's probably unrelated to your breast. I think mine is probably to do with posture - I find that I lean more to that side when I'm sitting which puts more pressure and strain on that area. And I only notice it when I'm sitting, it goes away when I lie down or when I'm moving about. So try and think of logical reasons as to why you are getting pains in your back and shoulder, and consider how the pain is presenting. It's most likely to do with the muscles but I know it doesn't always stop those thoughts creeping in. We just need to fight them with sensible thoughts.
But I made the mistake and I think you did too, of Googling that symptom and then the seed was planted