Hi Bella
so sorry that you find yourself in this forum. Your pain can be caused by many things, and I pray that it is something harmless.
I had a 7cm tumour, which could not be felt - I only had a feeling of breast tissue being pushed forward, then I had a leaking nipple which went on for quite a few weeks - I had already booked an appt with my gp regarding my breast feeling 'different' and the leaking came before my appointment. I didnt feel ill, didnt have pain no other symptom other than a strange feeling in my breast. I had a harmless lump removed 15 years ago, and I only found it because I check my breasts daily in the shower, hence I felt something different.
Good luck with your appointment hun.xx
Christina x