Breast Worry again

Hi everyone 

I've been on the forum before and had lots of support so posting again as I am worried sick about my breast. In February last year I had left breast pain and my nipple which was already slightly inverted (bad enough to prevent me breastfeeding) looked different and more pulled in.  GP referred me breast clinic where I had examination and mammogram which revealed nothing sinister so was told hormonal, non cyclical pain and to use pain relief and it would pass. I had been on HRT for about 9 years at the time so was happy all seemed good. Fast forward to July  and pain still there so was referred again to clinic as I was still not re assured. In August I was seen again at clinic and had an ultrasound of upper breast where some nodular tissue was but this was cysts (like bubble wrap was how it was described). 
Since then I have been in pain but had another routine mammogram in September which was also clear. 
I now have a tight pain in my arm on same side, and under my upper arm. My nipple is painful when I am cold as well as my breast feeling tight and swollen so I am totally a mess with this. It doesn't help that I stopped the HRT due to this in panic! 
I am now going back to my GP on Tuesday as I just don't feel this is right at all. I can't sleep now with the worry as I'm convinced something is wrong. 
Had anyone ever experienced this?

I am so worried