as much as i would like to address your concerns i really do not know anything about you. your age medical history or even if you are a female (men have breasts too). more importantly it would take a thorough examination to determine if this lump is worrisome or not. although i am sympathetic to your lack of insurance an examination is really the only way to make this important call. i can tell you that lumps that come and go are more likely to be cysts especially if the lumps are influenced by your menstrual cycle (again assuming you are female). breast cancers do not come and go. sadly they tend to stay and get bigger over time.
i have a lump in my right breast that keeps disappearing and reapearing. i have had a lump removed before but the doctor didn't tell me it was cancer or anything and it was in the same breast. but sometimes it is kinda tender but when it disappears i am fine is this something i should be worried about? should i go get it checked? because i have no insurance