Hi ! Good evening. I am Dr Shareef answering your query. Even though it needs a personal clinical examination of the lump to diagnose, from your history, it seems to be a collection of blood (hematoma) resulting form the trauma to your leg. The pain in the lump points to the fact that it got secondarily infected and that it could have formed an abscess which is painful to touch. In that case, you need to take appointment with a general surgeon or go to the ER of your nearest hospital for a possible drainage of the abscess for a relief. 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.