What Causes Painful Bruise On The Foot Arch?

I have a bruise that you can see on the arch of my foot it is about 2 inch long and an 1 inch wide i noticed my arch hurting last thursday now it just keep getting worse i didnt notice the bruise until today it kills me to walk when i walk my whole foot hurts. I am 32 years old i am 5,5 and weigh about 140. I do not have any medical conditions.