I've had a few scares and been referred on the emergency system where you are seen within days before now so if there is a major concern (for example, if there is tethering on the skin) they tend to move a lot faster.
The couple of times I was referred, the team were fantastic, seen by a breast surgeoen and specialist nurse and had an examination, ultrasound and biopsy (fine needle aspiration) on the day and, one time, even got the results the same day.
It is scary, when they fastracked me and, on top of that, I was more worried as they said there was tethering. I didn't have a GP at the time and they wouldn't let me leave the walk in centre until they had got me booking in with a local GP as an emergency to see them to book me into the breast clinic where I was then seen very quickly.
They were just harmless fibrous adenomas - most instances are harmless (if scary) but you are doing the best thing getting it checked out.
When you say "on your breast", do you mean as in visible (eg on the skin) or actually inside the breast itself?
Let us know how you get on x