What Could Throbbing Pain,lumps In Leg With Discoloration Post An Injury Indicate?

I banged my leg in July 2014 my leg was very badly bruised and swollen and sore. 3 days after I was on a flight and my ankle and leg was black. After a few days my ankle cleared. However my leg is still black, swelling gone down but I can feel lumps around the place of the impact. Leg continues to throb and ache from time to time. What could this be?