If you are like me and have a desk job, your fretting hand is weak. It took me 3 or so months to build some strength up. OTOH because Chuck Norris does one finger pinky push ups while he sleeps, barre chords came really easily to him. Just give it time. In the meantime, try alternate between playing open chords and barre chords to your fretting hands a rest. For example, play the verses of a song using open chords and play the chorus in barre chords. That way you get a rest within a song. ps wait till you start on bends. then you will find out how weak you are all over again.