It sounds like you are used to the Laz-e-Boy riding position of a cruiser. That is, an upright position with elbows lower than your hands and knees vertical to your feet.
The RS has what I call the semi-sportbike position where you lean forward a little, reaching down to the bars with your feet behind your knees. It's a position that many find to be uncomfortable, especially older riders who may have back or shoulder issues. They usually install barbacks to raise and move the bars closer to them so they can sit more upright.
I am 72 years old, 6'1" and have both RT and RS model bricks. While I can ride the RT from sunup to sundown, the RS starts to get a little unpleasant after only 4-5 hours. The personalities of the two bikes are different and guided by the riding position. The RT is a mile muncher that is intended for covering massive distances in maximum comfort while the RS is for quickly negotiating twisty roads with maximum fun and minimum fuss.
As Laitch mentioned, there are places you can go to see the seating position of your bikes. It might help us here if you can describe the exact problem you are having. Is it back, neck, shoulder or leg discomfort. Many here have found ways to make their RS's more user friendly.
