You are suffering from old gun shot wound associated with osteomyelitis
. You have not mentioned about the present condition of the wound and what treatment was given for osteomyelitis.
is interconnected with osteomyelitis. unless osteomyelitis is corrected full wound healing is not possible. X-ray will reveal the position of osteomyelitis - Treat that first, the rest (pain)
will disappear. If you are a patient of DM take care of your diabetic status.