I put bars on before adding a backrest. Tho my comfort level was 10000 times better I still had some back pain cause I tend to slouch when riding for a while. After adding the backrest any pain I've felt is gone. I haven't gone very long distance but I have no doubt that it would be very comfortable with my set up

 

My bass says he's sore as hell after riding too, and that I should have left him in the lake where I found him.

 

Bars: Wild one 570's stopped pain between shoulders and wrists. Sundowner seat moves me forward to much (6'1", 33" inseam) like backrest but not the look of it

 

Backrest for sure. Highway pegs to stretch the legs. Bars are more for arms/neck and maybe upper back. If you go all chrome, yes, nearly $1,000 with HCC, pre-wired, preinstalled controls and perches.

 

Apes are comfortable, backrest really can add some comfort....

But I doubt that either one of those will address a sore *** or knees.

For the butt the absolute best thing I have found is the airhawk seat pad, it is amazingly comfortable. It is also UGLY. For me it is worth it on my touring ride.

The next best thing is modifying your seat with some comfort foam, or getting a different seat.

For the knees you gotta stretch them out some...either a little with the harley goodies floorboard extensions, or more with some highway pegs.

I have both on my ride.

The pic below shows the highway pegs I am running...so in addition to getting the legs stretched out for the knees...those pegs are adjustable while riding and I have an infinite # of foot positions.

 

Holy crap! Those look like a set of Shimano DX pedals from the 80's. Nice!!!!

 

Thanks man!

Here is a video of a bunch of different style pegs.

These pegs are produced specifically to increase comfort while riding by giving lots of adjust-ability AND a larger platform than a traditional peg ...and too look good! Oh, and for the go-fast guys, with the trap and traction pin style, no more foot slipping off the peg at speed!

http://www.youtube.com/watch?v=-7cptFNnYeU

 

Adjustable backrest was the best aftermarket investment I've ever made. Get a backrest & some highway pegs and you should be good to go, IMO.

 

If it's your butt and knees that hurt, you need a better seat, and some pegs to stretch
out your legs, like most have already said.
I have a bad back, and could not ride without a backrest, with properly placed
highway pegs, you can push your back into the rest for maximum comfort.
With my back, I tried a few seats, the best was my corbin close solo, custom order
with softer foam than they normally use. Their regular foam is hard as a rock,
and takes some time to break in. With the softer foam, the seat was comfortable right out of the box! Man, I love that seat!
Secondly was a mustang backrest, very adjustable, and comfortable.
I have a corbin backrest too, but it's not as comfortable as the mustang.
I use the HD short angle highway peg mounts, but they are mounted low, so I don't have
extra strain on the back from having the legs too high.
I could never see how it would be comfortable with the highway pegs some folks have.
Looks like they are on the OBGYN table, ready for an inspection. LOL

The more options you have to move your legs around the better, riding stuck in one position for hours can be very painful.

 

Need to know more first.

Does the bike "fit" you properly? How tall are you, and how long of an inseam do you have?

Might not be a bad idea to take your bike to a dealer that has a "fit shop" and have them take a look at your riding position.