I noticed a problem three weeks ago very similar to what Oops has just described (but no pain).
After keeping an eye on it for a few days, I decided it would be stupid to do nothing, and rang my surgery, fully expecting a phone consultation. Instead, I was given a face-to-face appointment that very afternoon (my first time out of our safe bubble since lockdown). The doctor doubted it was serious, but said they routinely refer people with any changes in their breasts to the hospital.
Exactly a week later, I had the hospital appt., and after an examination and mammogram i was given the all clear.
If I hadn't gone, even though I had suspected it would be just another side-effect of aging, I know that I would have always had some doubts and fear in the back of my mind, haunting me in the early hours as these things so often do,
Go as soon as you can. Either it will out to be nothing and you can stop worrying, or if, Heaven forbid, it is something more sinister, you will have the best possible chance of a successful outcome. Do it, and good luck