What guage strings are you using?
I'm using .16 for the 3rd string and don't notice any problems with it, even using the pinky finger. 2b5 is relatively easy as well as long as you don't mind a little pain :).
If you're having trouble, try bending in the opposite direction. I find that if you pull downwards it's a lot easier on the lower frets. Basically anytime I need to use the first finger to bend, I'll always bend downwards (towards the floor), then bend upwards most other times.
If you're still having problems, try using two fingers.
Best bet though is go with a lighter guage of strings. until your fingers gain some strength. A good guage is a hybrid set: 9, 11, 16, 26, 36, 46
That gives you lighter strings up top for bending & heavier on the bottom so you can still get some good chunking out of em.