Hi! Good morning. I am Dr Shareef answering your query. This could be an old hematoma (collection of blood) following the trauma on your back, which has now organised instead of being absorbed, or this could be a benign cyst/lump on your back not related to the past trauma. Even thought it did not create any problem yet, for knowing exactly what it is and for cosmetic reasons as concerned by you, this could be removed and sent for a histology report. For this, I would advise you to consult a general surgeon in your area, who after a physical examination and related investigations, might be able to tell you the exact details of its management. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. I wish you an early recovery. Dr Shareef.