Tightness in right hamstring?

Recently while running i felt a tightness in my right hamstring, or what i believe to be my right hamstring. i immediately stopped running and stretched my hamstring as much as i could. a couple weeks later i still sometimes feel tightness in the upper part my leg. before i exercise i make it a point to stretch it out but it seems like its right above the part of the hamstring i normally stretch out. im afraid if i continue running it will tear eventually and i have a firefighter physical test to take very soon which i want to practice 100% for but im afraid i can hurt myself if i do. im asking if anyone knows what i could do to stretch it out and/or how long should i rest to recover? im 20 years old so i should recover relatively fast and ive never had a problem with my hamstrings or legs before