Was running hard for 2 month, now having heartache, please advise!?

I am 29 year old male, 5.7", 140lbs, decided that it's time to get my fitness in order, my new year's resolution. Decided running is the best, last time ran in elementary school and then again 10 years ago when tried to catch the bus. Started running in January, 2.5 miles distance, was hard at first, but in a week pushed myself to run the whole distance without stopping, thought would p out on a road, then pushed myself for 2 month everytime to run whole distance. Stupid mistake. After 2 month of "health training" noticed that my heart starts to beat like crazy out of the blue, just sitting in front of computer and in the mornings. Stopped running immediately of course. What could it be? What did I do to my heart? How long do I need to take to recover and start running again? Recently bought heart rate monitor, after 1 minute of light jogging my heart rate is 170! Please, any advise.