Hi, around Christmas time last year I experienced a dull ache in my right breast at the side, the tissue in that breast is definitely more prominent than the tissue in the left breast anyway however it was also my armpit that felt dull and achy. After a couple of weeks my shoulder blade started to ache on and off through the day every day and also sometimes the ache would go down my arm sometimes feeling what I describe as a cold sensation and also my wrist. I went to the doctor’s multiple times and no one could find any lumps or swelling etc. I can’t feel a lump myself. After this lasted a good couple of months it finally went away (all of the symptoms from breast to shoulder and arm) the doctors and A&E doctors all told me it was probably nerve damage from carrying my then 6 month old around. I was so paranoid it was breast cancer as I know it doesn’t always form a lump. 
So after a good fair few months with non of this happening this past 2 weeks the feelings have all come back, my right breast feels tender again and under the armpit feels thicker to me although when I look in the mirror there is no obvious swelling. I have shoulder ache on and off again with it travelling down my arm occasionally. A few weeks ago both my nipples felt so sore one day (nowhere near my period due date) and then that night I got in the bath and they burnt like hell! I noticed they had little red scab/sores on them - this was in both breasts. I’m not sure if that’s even linked to the achy boob or if it could be separate like a thrush symptom. I feel like the doctors will just fob me off but with all these coming back and my boob/under armpit feeling burny I’m just so worried!!!