Going through pre-menopause phase. Worried about a sore spot on right breast. Was on medication for an infection on right arm

Hi, i am a 48 year old pretty healthy female. I have a sore spot on my right breast near the end of the breast closer to my arm. Generally it is only sore when i push on it. Kinda feels like a sting but goes right away-think im going through pre- menopause . I feel it the odd time when i bend forward or when lying down but just a little and i dont feel any lumps , although my breasts are pretty lumpy to begin with. I have never noticed this before until 3 days ago. I had C Difficil this time last year because of the medication (Clyndimicen) they gave me for an infection on my right arm but thats all good now, but i do have some tummy issues like lactose and i think gluten free now. My stomach has never been the same, not sure if this has anything to do with breast or not just thought i would let you know. Thank you, Christine