Costochondritis as a cause of breast pain

im 25. My mentrual cycle went haywired a couple of months back. After 10days of period, a week break then another cycle starts. My mum said its not menstruation. You have any idea what it is? It might be the reason for my worry on my left breast. Just discovered it about 3days ago. When i press against the lower part of my breast, nearer to my sternum side, i feel a lump. Its not a soft lump but feels like a swollen bone, as if a 5-cent coin portion of the rib bone is swollen. It hurts when i press it but dont feel anything when i leave it alone. I dunno whether to worry about it or think i probably hit somethg since im quite cluelessly clumsy.Do help ease my worry! Thank u!

THE BREAST DOCTORS SAY:

Menstrual irregularities are usually the result of hormonal fluctuations that can cause breast pain at the same time. However what you have described appears to be unrelated problems as your breast pain is likely to be due to costochondritis, an inflammation of the cartilage that connects a rib to the sternum. This causes a sharp pain when you press the costosternal joint- where your ribs and sternum are joined by the cartilage. The causes of costochondritis are largely unknown but can be due to injury, strenuous exertion or a rare condition called fibromyalgia. Majority of cases resolved spontaneously in a few weeks if left alone although anti-inflammatory drugs or muscle relaxants can help expedite the recovery.