What Could Cause Bruise On Leg Below Calf?

I got a quarter size bruise on my leg below my calf that appeared there without hitting myself. As time passed it started to spread and has now taken over my leg from my calf to my ankle. My leg feels tight, sometimes has burning sensation and skin feels hard around the bruising area. I did break my leg prior to this and was wondering if that had anything to do with this. I need help... Thanks but I dont have the money.