I find myself having unexplained bruises on my legs, for which I cannot seem to recall any moments in which I hit them on anything severe.

These bruises usually appear knee and below and are extremely ugly with various shades of blue and purple, and are also very large in size.

I have extremely flat feet, and have found that when I wear uncomfortable shoes is when these bruises appear. Is that possible?

I also bruise extremely easily on the rest of my body...Not sure if that is related.

Obviously, the answer would be to wear comfortable shoes, insoles, etc. But i'm also more interested in knowing what this is/what it means.