bruise on ball of foot

3 weeks ago I developed an intense pain in the ball of my right foot which lasted about 5 minutes, I thought I had stepped on a bee, I was barefoot, Within 15 minutes the ball of my foot swelled up so that when I walked it hit the floor before any other part of my foot and it was very sore -later that day it suddenly started to bruise on the bottom of my foot by the ball and then continued around my small toe and continued on a straight line just below all my toes -it was very bruised – I let it heal and and now a few weeks later it did the exact same thing –what is this I’m in good health and a runner but wear excellent running shoes and have never had this problem.
Thanks.