Hi, I just recently turned 20 and since March I’ve noticed before my period I get a stinging pain on the very side of my left breast. it feels like somone is pinching me, This freaked me out so I had a breast exam done about 5 months ago and the doc said I was fine. I will feel around that area just to be safe (which gives me so much HA) but I don’t feel anything suspicious. I feel fine but I still get this pain, and it’s only in that area. what could this be??