really sore lump in nipple

[mamadonna]

Hi,as the title says really.
Friday night i noticed that my right nipple was sore ,with ttc i thought that maybe this was a good sign,but as it persisted i got a little worried so i went to have a check and noticed a small lump and its really tender to touch,does anyone have any idea as to what this could be,I'm gonna make an appointment to see my doc in the mornin as slightly worried,any info is much appreciated thanks