I would imagine hormonal levels, but that would have to be some pretty drastic hormonal changes daily that would surely evidence in other ways. Have you brought this question to a doctor?
No.. I don't go in for another appointment in months and there's no way to move it up
Breast size may increase or decrease during the menstrual cycle due to effect of hormones but it does not cause daily change as hormone levels do not fluctuate so drastically. If the symptoms persist then get a hormonal assay done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
What about if I am not on my period Sometimes they will be really close together and then they will space out and then go back to the way they were