Bruises without being hurt are not normal. It means that your blood clotting is not as it should be. What this means is that if you cut yourself the blood doesn’t stop well and you loose more blood than you should. Similarly as the capillaries break under your skin which causes the bruises they could break somewhere else and, God forbid, cause more serious problems besides the visible ones.
I had this few times in my life and it can be treated, just don’t leave it too long. If you are prone to it (I am) taking all the vitamin C and other supplements thin out your blood even further and this happened to me at the beginning of the treatment so I lower the vitamin C doses and stopped taking supplement which contains Pau D Arco (blood thinner).
Go have it checked out, definitely!