it sounds like the bike you have now must not be the correct size or is not adjusted to fit you. if you have been riding for a year the style of bike shouldnt matter for 10 miles without pain. it was definately easier for me to put miles on after switching from a mountain bike to a road bike. make sure what ever bike you get fits you if it hurts to ride you will find reasons not to ride.
now for the bike dont just look at the price go to the lbs and test ride several bikes. go to several lbs and test ride several bikes. you will find the bike that wants you. i really like the way the specialized bikes ride and handel and the entry level allez is not to much above your upper limit. the mountain bike i had was a raleigh and i have a older raleigh road bike they are good bikes. good luck on your journey and buy what feels good. and go ride......