I used to run all the time when I was in the Air Force. I never experienced this fabled runner's high. I did experience runner's knee and shin splints.
Ouch, those both hurt. I've had both, yet rarely if anymore. Because I wrecked up one knee, its more likely to occur there, but beyond that what I do to decrease the likelihood of the first, run on the front of my foot the whole way, but I don't mean the toes, and I no longer run heel to toe. Regarding the second, I try to spend a decent amount of time stretching. Although neither of those are probably absolute solutions.
As for experiencing runner's high, thats a bummer, but I do recommend that early on in the run, just use it as a warm up, don't expend yourself too much too soon, make it feel like a walk in the park rather than a massive intial effort. Eventually the body will start clicking along smoothly and the run can feel a bit like it is some what effortless. Thats kind of a way to explain a runner's high.
