Hi I am a 42 year old female who has had a spongy feeling lump on my arm pit it looks and feels more puffy and swollen rather than a lump its not hard it don t move but its been there for about a year and won t go away here lately my chest has been hurting and sometimes my arm does I m worried it could be breast cancer I ve had a mammogram done and they said it wasn t cancer but they also said they can t see very well because I have dense tissue breasts so I m still concerned