Beginning guitarists often avoid playing bar chords.They can be physically challenging for the left hand.Cramping and pains are normal but in time they become as easy to play as open position chords. Here are a few tips to make them easier.
1. Keep your 1st finger close to the fret
2. Play a little bit on the side of your 1st finger.
3. Keep the palm of your left hand away from the neck. (this will
help keep your 1st finger flush against the fingerboard)
4. Keep your other fingers arched.
Below are 3 common major and minor bar chord forms.These forms can be played at any fret. The name of the chord depends upon which fret and string your lowest note is on (this is called the root note). Example – the first major chord form below played at the 3rd fret would be G major. If you play it at the 5th fret it becomes A major etc…
To understand this in more detail, check out my blog on How to Learn the Names of the Notes on the Guitar.
I hope this helps!