Hi Rebecca :-)
Everyone, fit and healthy people who have never had a sniff of cancer go through small body changes all the time. We are very complicated biology. These things come and go, mostly they are harmless and mostly they sort themselves out without any assistance from medical people. The difference for you now is that you are being scrutinised three times a year so sooner or later something 'interesting' is bound to come to their attention. So far I've had 3 out of 6 exams where something worthy of further examination has been found. They have all turned out to be nothing important but they absolutely must be checked out. I hope you find this is the same in your case. I also know how very difficult it is not to worry so please just take comfort from the fact that most of these funny littrle discoveries are nothing sinister at all.
Please let us know how it turns out!