One trick that will make your life easier is to place your barring finger in a way that your articulations fall on a string. The fleshy parts of your finger are not your friends! Also try slightly rotating the finger to find the edge with less flesh on it. You will need way less pressure this way. It is true that you need to strengthen your fingers, but brute-force methods have the potential of causing serious injury. One very important thing I learned after many years of studying classical guitar is that if it hurts you are doing something wrong. 

Careful positioning of your wrist and fingers (also the position of your thumb is very important) might drastically reduce the amount of pressure you need, and make sure you don't have your wrist too laid back. It should be in a position that allows you to use the strength of your arm to exert pressure and not only your fingers. Many rock and folk players tend to use their guitars too low (you can tell by the thumb almost being able to touch the fretboard), and this demands more effort from your fingers.

Another useful piece of advise is using lower tension strings while you are learning. Usually very thick metal strings in an acoustical guitar is asking for trouble, and among nylon strings there are usually low tension models. They don't usually sound as good but you can switch to higher tension when you master those strings.