I Have A Spontaneous Bruise On The Lower Left Side

i have a spontaneous bruise on the lower left side of my stomach, just above my panta-line on my hip. I have no idea where it came from and there is a little swollen bump under it. The bruise is very dark in the middle and the size of my fist. I am in the military and lift heavy things often so I am worried it may be a hernia. What do you think?