I would say that you likely do need to figure out how to slow down for your running intervals. It sounds like you've taught yourself what your body is considering a sprint, but most people can't extend their sprint pace beyond a certain length of time without going anaerobic. You may be able to adjust your gait so that your knees and shins aren't hurting - or you might need to get a pair of shoes that is better suited for your feet and your running style. Were you fitted for the shoes that you're wearing in a running store?