One of the problems people have when they bend strings is that the strings above the one their bending will go up over the top of their fingers. That causes some bad tones when it happens.
So, when bending, use the fingertips and curl the hand around the neck of the guitar, so the knuckles (at the base of your fingers) are past the bottom of the neck. Pushing up from here will make it easier, but you will still have to build strength to improve.
Keep practicing hard though. This technique is one of the most soulful things you can do with the guitar. Soon you will create a signature sound of your own like many great guitarist have done that makes them recognizable when you hear their music.