Hi,
You should definitely speak with your doctor about the pain you're experiencing so that you can figure out if this serious, or not. Your doctor may suggest a breast health exam and mammogram/ breast screening. Meanwhile, you might also want to do a bit of research about perimenopause and mastalgia (the medical term for breast pain) to see if any of your symptoms match the descriptions. Your breast pain could be due to hormonal changes in your body because you might be perimenopausal (?) at 45. I had the same experience as you have had, after my 45th birthday this year, and found out that I am perimenopausal. For the pain, I apply a warm compress to the breast and take either Ibuprofen or acetaminophen to help relieve any lingering pain. Ditch any tight fitting Bra's. Your doctor will probably have better suggestions for dealing with breast pain and more helpful treatments...
I am also a cancer survivor, believe me I know how scary it can be when it comes to dealing with another unknown health issue, that's why it's so important to get the right information from your doctor as soon as possible. Stay Strong and Be Proactive!!!
Best Wishes :)