Advice information - pain in breast, waiting for ultrasound

Hello All, I am looking for advice, I had a breast scan a couple of years ago and found I had cysts in both and dense tissue in my left breast.

Anyway 2021 2 weeks before my last period my left breast was very painful and my nipple really sensitive ( like when I was pregnant long long time ago ) I'm nearly 42... Anyway it went a little calm after my period still there but calm then ovulating it came back, I had my smear test at the time and when she checked my painful breast she said straight away it needs to be checked, the pain is where the dense part of my breast it under my armpit, she wrote for the ultrasound scan appointment they need to check my cyst in my left breast.... But I have also had a sore itchy armpit on my right side and wonder if it could be related, I know it would normally be on the same side of the painful breast if related together but my mind is working overtime and my ultrasound scan isn't until the 26th of March. Now I don't have as much pain but a strange feeling in my boob like there is a big lead weight inside it and if I touch the area there is pain....

Any advice or info would be greatly appreciated

Thank you Cassie