A Spot With Deep Hole And Stingy Goo Under Armpit.Is It A Symptom Of Breast Cancer?

Hello. I have had a black head like spot under my armpit for about two months now, and it was almost felt like a lump. A few weeks ago I decided to pop it with a pin and a thick, string of white goo came out. I then left it thinking it would clear up. But tonight I realised it was back again. I done the same, with a pin and a lot more stringy goo came out, and I realised this hole was very deep and I could nearly fit a whole pin in this hole with no pain. Almost like it had been pierced. Then I realised another small hole, but no puss. The second hole was completely empty. The white stringy substance is not like puss. It s not runny. It s got a strange fish egg like texture is the best I can explain it. No pain and no smell. I m 16, 4ft 11inchs, very heathy diet, 130lbs, 7%body fat. My mother has breast cancer.