Why do I get random bruises on my legs after a hard run?

Again, been working out ALOT for the past 2½ or 3 weeks. I have noticed I am getting bruises in random places along my legs. They appear anywhere from my thigh to just above my ankles and range in size and color. Is this normal or should I be concerned? They don’t hurt, and I am generally in good health. Im 27 years old and I have noticed sometimes I get little spider veins from time to time that show up and disappear even before I began my intense trim down.