I want to start running 3 days a week?

Running is a high impact exercise. I hardly ever see runners well toned with muscle. When you have a pear shaped body the best exercises are squats. I suggest you work out with free weights working towards repetition exercises not as in power lifting. I recommend Complete Weight Training Book by Bill Reynolds. It has very understandable information for beginners who wish to train on their own without going to a commercial gym. You will learn how to tone up not bulk up. Your hips and upper thighs will match the top of your body and you will change pear shape to a beautiful athletic body. This is physical fitness that you can do in your own home in all kinds of weather conditions. You spend one day working on upper muscles and the next day on lower muscles.