Hello. Thanks for posting your query. It might be soft tissue injury or fracture. . Large lump might be due to haematoma formation(collection of blood) from rupture of microvasculature or from bleeding fracture ends. Without X-ray, it is difficult to differentiate a fracture from others. I suggest you to consult an orthopaedician nearby for a detailed examination. You may get the X-ray of the area affected under his/her guidance. In the interim,apply ice packs to the affected area,anti-inflammatory drug like motrin to reduce pain and inflammation. Avoid putting weight and rest well. I hope this is helpful to you. Wishing you good health... Regards. Dr Saurabh Gupta