My iPhone 4 power button sometimes gets stuck?

I have to push it down really hard, is there anything I can do MYSELf?

I was also having problems with my phone until I found Assistive Touch! You have to go to Settings>General>Accessibility>Assistive Touch>On. A little button shows up on your screen. You can move it to any corner that you like. Once you click it, there are many different things you can do.Click on lock screen and it will turn off your phone. This device also has a lot of many other helpful features.

Note: I have iOS 6, so either you might have to go through a different path to get it or it might not be there. Hope it helps.