<s>[INST] im a 13 year old male and have a lump on the center of my chest where the ribcage meets just under my breast area. i have fractured or broken one of my right ribs before but got an x-ray and it healed ok. i notice sometimes when i turn or move a certain way i will feel a slight pain one the lump. it feels like the lump is actually part of one of the ribs. what could be the cause of this??? [/INST] Welcome to Chat Doctor. 1. The possibilities are bony out growth, cartilage growth, lipoma. 2. This needs to examine first and ask for an X-ray chest lateral view to concentrate on the area of lump - to see any out growth.3. If capable mass is seen over chest - then worth to have FNAC - fine needle aspiration cytology to know what cells are involving (fat cells / cartilaginous / bony and so on)4. To find out internal chest wall involvement CT computer tomography will be definitive in this case (though its radiation) we need to know if there is any growth which can be prevented earlier than in later state.5. Sugget to get the above investigations done and treatment or remedy depends on the findings. Good luck. Hope I have answered your query.Anything to ask do not hesitate. Thank you. </s>