O Tests -ve but Sore Breasts

I have been a bit mickey mouse this month (first month I have started O-testing) because of having migraines and working long hours (finishing in one week) so I did stop the pressure of O-testing, but began again recently since my breasts have become tender.

I have not started charting yet but will look into it I think... I just expected my O-test to be positive with my breasts being so tender. How long does the LH surge last? Can you have a -ve O-test even with O-symptoms?

I have read that O-tests don't work for everybody, and others swear by them? Any opinions/ what are your reasons?