i was the one that never found barre chords uncomfortable, its not the problem on acoustic either, the problem is wth the steel strings on acoustic i find them hard to use one finger to press all of them down and get the note sound of one string due to my finger not be able to put enough pressur on it, the problem is that im trying my best to pressure on it, but it never works, also ive been doing finger exerise for long time so i dont know whats up?

i starte thinking that it was because my fingers are really small and skinny for a guy but i also thought it was an adavantage for guitar players lol
Just keep doing it, eventually your finger will become harder and it won't hurt.
legit are fingers can evolve to be more harder....HELL YAH!

lol im slighty joking there but really i never knew that lol but then again iam 15, have lot to learn about life :P
One thing I always advise is to have the guitar's action checked. If the action at the nut is too high, it will be very difficult to properly finger barre chords.
You can easily check this by putting a capo at the first fret. If it's much easier to hold the chord with a capo in place, then likely the action at the nut needs to be adjusted.

Other than that, try playing the notes of the chord individually so you can isolate what's wrong. Sometimes a simple shift in hand position will work.
I play classical guitar a lot and barre chords are used pretty frequently. They gave me issues for a long time because my hands seem to be similar to yours. I noticed it giving me the most problems when I was first learning "La Catedral" by Barrios which uses barring. What I found was that if you keep applying pressure like you say you do (and what I used to do), that will give you a muscle cramp in your hand before anything. The pressure you generate by squeezing is not significant and not sustainable for a long time. The way you should approach it is to let the weight of your hand and subsequently arm weigh your barre down. The actual pressure you're applying by squeezing should be very minimal. It felt awkward at first but after getting used to it I found it to save my left hand. Scott Tenant has this approach in his book Pumping Nylon which helped me iron out some bad habits. Hope this helps!
I can only think of two things that could help you out. As was mentioned above you could file down the nut. This will make barre chords easier. A lot of less seasoned guitarists have trouble with barre chords. Most of my friends who also play a little guitar try to play barre chords but they sound like crap (sorry friends, but its true). I have a little bit of trouble on an A shape barre chord when I'm feeling lazy and my hand positioning isn't quite right. However, even on one guitar of mine which is a piece of junk that was built in the 60s which has very bad action, I can't manage any barre chords that sound somewhat decent.

The other reason is you just need more practice. Bikewer gave great advice about playing the notes individually.