BHM, you didn't mention how long you have been shooting or what your specific experience has been with a 1911. IF you just got the 1911 and just got it in .45 Auto, there is definitely a learning/experience curve. The following are some very specific observations, having just returned from the shooting range today and shot 3 designs. I shot a 9mm Browning Hi Power, with both 115 JHP and 147 Subsonic, an EAA Witness (all steel) in .38 Super +P and a Springfield Armory Champion in .45 Auto with good old 230 grain Hardball.
First off, the other two weapons you mentioned in your original question are both wider in the grip area that meets the web of the hand. The 1911 design can at times, depending on back strap AND grip safety, be a bit punishing. This is just the way 1911s are until you are used to them, comfortable with them, and tuned your load to your requirements.
Both my "non-1911" guns of the day have the wider grip in the area for the web of the hand to have recoil impulses distributed. Both my smaller caliber weapons of the day were VERY comfortable to shoot for me. I have been shooting informally for 35 years. Even shooting the .38 Super in +P is a pleasure compared to shooting the 1911 in .45 Auto. Gotta remember, the impulse from a 138 grain projectile, even at +P ratings is much less than a .45 Auto hardball in 230 grains. It is a combination of the physics of the round and the design qualities of the gun.
The 1911's narrow area of the grip safety can definitely have one notice the more robust recoil of that 230 grain projectile. BUT, I also enjoy shooting the bruiser. After a good while, and this is not just to be macho, you just enjoy the pleasure of knowing you are launching a heavy projectile down range. This has little to do with the "gaming" of competition shooting. It may just take a while to get used to shooting the 1911 in .45 and finding a comfortable shooting grip and appropriate round to shoot. Try one in .38 Super. I suspect you would enjoy the 1911 much more.
Guns and rounds can be tailored as suggested by most of the responses. If you just have to have the .45 auto, put some light loads through it and use those for a while, then work your way up.