Glad you went to the docs ... they'll act pretty quickly on any breast lumps, or in my case a lump on the testicle.
expect an MRI or CAT scan, or both.
this site explains 'tethering' a bit ...
http://www.cancerlineuk.net/article/515603.asp x
and these guys are great if you have any questions ...
http://www.cancerbackup.org.uk
hope it all goes well for you ... keep us posted.
You'll find we're not all malicious on here, and can be quite supportive if you need us.
Naz x
expect an MRI or CAT scan, or both.