One option is a mirrored colemak layout.  Sample pic from Dreymar's sig:

Before taking such a radical step, however, I would suggest reexamining your typing very carefully.  What alarms me the most is:

Floating is just as important in colemak/dvorak as in qwerty.  While going for keys, you should be (for lack of better word) floating all your fingers along with the active ones, in the manner that makes you most comfortable.  Keeping certain fingers "locked" is just a recipe for strain.

Even in the "home row" position, the middle and ring finger should be floated somewhere between the home and top row - they simply don't rest naturally in a single line.

Try hitting ;: with your ring finger (while floating, of course).  I think I would go crazy if I had to hit it with my pinkie.

My wide layout (see AltGr pic below) may have also helped with pinkie strain, by moving /? from the pinkie to the very strong index, and reducing the distance to Return, at the (at least in my experience) relatively minor cost of moving '" to top row.

For vim, some of us prefer a colemak.vim/colemak-evil-type configuration, which makes the keys a bit more geometrically-oriented.  Others still prefer the default layout for its mnemonicness (possibly just remapping the direction keys, or else using modifiers to add other direction keys - see Dreymar's extend mappings (in his sig), my AltGr layout for examples).

If you check my initial posts, you'll see me moaning about the same thing.  I had days where I almost gave up entirely, and experienced loads of pain even after months.  One  thing I must add is that I already had computer related injuries, and that's why I eeked out an alternative layout in the first place.  I was new to touch typing and boy did I feel it.  Even now I'm not entirely comfortable with touch typing;  I have good days and bad days.

You've pretty much identified the problem.

Qwerty is very left hand orientated, as such, you're not used to typing with the right.   I'd never used my pinky and barely used my right ring finger.  When you start out with Dvorak, it suddenly feels like a complete over burden on the right hand, because you have barely used it previously!

I'll guess that the way you naturally settle your hands with Qwerty is to rest your right fingers more on the U,I and O keys.  Changing to sit them on the home row, feels very strange also.  The standard keyboard makes this doubly irritating, and can also strain he wrists.  I'm not sure how you hold your fingers, do you curl them or type with them more extended?   I think you need to have a good curl on them to settle them on the home row.  You might never have had to do so under Qwerty.

When you are starting out you can't relax your hands, you are very conscious of where to place your fingers and that can be straining as well, especially if you are stretching to the keys rather than floating.  Floating comes more easily when you gain confidence and practice with typing.

I'm tempted to say that you'll get used to it, if you are prepared to ride the storm. For me though I'd give my right pinky up for typing comfort, so if you already have that, and a reasonable WPM; I don't know if I'd bother rocking the boat.

I went from a hunt and pecker with neck and should problems (no hand or finger issues), to a touch typist with some finger and wrist strain (less neck issues.)  I can type more freely than in the past, so that's a positive gain - I actually couldn't use the computer at all for a time, and laptop use hunting and pecking Qwerty (say tech support for family and friends) can soon bring back the onset of pain.

I actually quite enjoy typing with my right pinky, but I do wonder if it still strains me further up the arm, or means that I can't straighten out my wrist more freely.  Perhaps I'd be more comfortable using my stronger fingers.  It's so hard to ever know, as the investment in learning another layout is so high that you don't get to compare these things.

If you want to lessen the impact, you could try a modified Qwerty layout,  something like Minimak (4), or you could could try the Tarmak route to Colemak.  The Minimak (4) looks like a clever hack to me.  If you are a good Qwerty touch typist, then it seems a shame to loose some of those benefits.   I settled on Dvorak as I'd not learnt to touch type Qwerty previously.  Colemak is designed in part as an evolution from Qwerty (I believe it's heavily inspired by Dvorak.)  If you don't like homerow typing, and don't feel you ever will, the Minimak (4) looks like a good choice.

I might add that I've had no real experience touch typing Qwerty or using Minimak!

The tarmak transitioning itself would not help very much with OP's problem, because the changes in finger usage are not very gradual:

(Tarmak 2 omitted since it doesn't change anything on the right hand.  The pinkie and ring stats would look slightly more balanced if OP uses ring finger to hit qwerty-P.  Here are the tarmaks in case you'd like to generate your own KLA stats.)

As you can see, most changes go even higher than the final colemak!  Thus, if OP finds he can't get used to colemak despite ergonomic/wideness/persistence advice, I would suggest either:

1. Pause at tarmak 2, which only affects the strong middle finger, confers decent advantages, and leaves the door open for a complete transition to colemak.

2. Go for minimak.  Probably easier to get used to and confers slightly better advantages than tarmak 2, but ultimately ends up not as good as colemak.

Due to being very conservative to qwerty, and mainly switching keys that are attributed to the same finger, minimak ends up with a very flat usage graph, matching tarmak 2 (at least on the relevant right-hand side):

(Minimak KLA exports found here.)

Since finger usage appears similar, the choice is then whether to leave open the possibility of colemak in return for some slightly lower stats.  Personally (I guess, unsurprisingly), I'd take that possibility.

If you have pains, don't switch layouts too forcefully. Tarmak might be a good choice, but more important is the general ergonomics.

Also, maybe a Wide ergonomic mod could help. It takes load off the right pinky (and the thumb if you use AltGr mappings), separates the shoulders better and helps you keep the right wrist straighter. Wide/Angle mods can be learnt without physical strain in my experience.

You could reflect upon an existing layout, or even pick a left sided one hand layout ;)

Has anyone tried a left hander?

I have been learning colemak for 50 days now and I do find that the 'OU' combo does get marginally stressful on the right hand after time especially when combined with 'Y' in words like "you", "out", "young" but words like "would" and "could" do roll very nicely however.