Blood filled bump under bra are

Has anyone else ever had this type of cyst before? It is underneath my breast, near where underwire sits. They hurt so bad and the skin is so thin on that whole area. Well today I got a sharp pain when adjusting my bra and noticed this large bump. It’s squishy but seems to be filled with blood and puss maybe? Anyone know what is it and how to get rid of it or why I got it?

TIA 😬