@onetruedog,
Let me say that I empathize with you on this. I pulled my left hamstring back in 2013, which came seemingly out of nowhere. I had worked my way up to 10+ mile runs on Saturdays, and made it about 1/2 mile in on a 6 mile run with a buddy and BAM!!! I was out of commission for the better part of a year. Sprinting all but guarantees a hamstring pull because of the huge stresses on large muscle groups.
I'm not a sports therapist, but I've been injured enough while running to feel fairly comfortable explaining what has worked for myself. I personally didn't feel 100% at the 9 month mark after my hamstring pull. I waited a year before I got back into any serious running. I can tell you that since I started back in 2014, my hamstring pain/sensitivity has waxed and waned off and on.
There's a huge psychological element that goes into running after this kind of injury because it is such a violently painful experience.
I've been able to overcome this in the past year through a combination of mindfulness and warming up. I condition myself to believe that my warm up will not harm my hamstring, then I proceed with 4-count jumping jacks, 4-count forward jumping jacks, [gentle] forward leg swings, and forward pedals.
I've been doing this warm-up routine for a few months now, and it's made a world of difference with the sensation in my hamstring(s). I'm finally back to being able to add in high intensity, longer distance sprints to the end of my runs; keep in mind these are distance sprints and not the typical high impact, short sprints.
Hope this helps.