What Causes Spotting Between Periods?

I spotted for 2 weeks last month then I got my normal period afterwards. now im spotting just very little every time i pee, i notice blood a little and sometimes there's a few spots in my underwear that is blood. im not sexual active, i don have any other symptoms, i don't have a foul smell to my area. what could it be ? also i'm always normal, i dont ,miss periods.