Hello, An MRI knee is advised. As any movement is painful after the fall this might need an MRI to understand the soft tissue better. Post which we can comment on the soft tissue injury. As the bump isn t going away on its own you definitely need to take up a scan so we can get the clear picture. Also, I will advise to take a scan and post which exercises like - static quadriceps, static hamstring, straight leg raise, reverse walking, knee range of motion exercises etc to be performed to regain the muscle strength. Hope I have answered your query. Let me know if I can assist you further. Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist