Over six years ago, I ripped my right hamstring in 3 places.
Last summer, I tore my left semitendinosis vertically, butt to knee.
I'm working on recovering strength, but I haven't been able to run without pain yet. Not pain in the hamstring. Pain in the left shin!
I'm not a sports physician or therapist, but I would be willing to bet that your earlier injury to your right hamstring has affected your running gait. You are probably favoring your right leg, which has led to the injury to your left semitendinosus and the soreness in your left shin.
You should consult a sports physician or physical therapist and get a thorough examination before you continue your exercise program. They might have you do a stretching/strengthening routine to ensure that both your legs have adequate strength and range of motion.
Torn hamstrings are common among athletes whose ratio of strength quadriceps/hamstrings is greater than 3/2. In other words, if your quadriceps are more than 50% stronger than your hamstrings, the hamstrings are more likely to become injured. Also, tight hip flexors - a common problem - can inhibit the hip extension functioning of the glutes, which leads to more demands placed on the hamstrings to extend the hips.
But enough advice without a shingle from me. Get yourself checked out professionally. And good luck with your future athletic activities. Let us know how you make out