Why are barre chords so hard to play?
Playing a full barre chord involves using the index finger across the entire set of strings. What makes this difficult is the tension of the strings and the dexterity needed to hold them all down at once to produce a chord that sounds clean and clear.
Some chords, however, are easier played as barre chords
In comparison simply moving the E Maj shape up one fret to play F Major, or moving the A Maj shape up one fret to play B was much easier than trying to play open F or open B. Fatigue can also play a role.
Classical guitarists may balk, but Jimi's 'thumb over the neck' barre chord technique allows him to position his fret hand in a way that those magical chord embellishments fall neatly under his fingers.
Barre chords are introduced in the RGT electric and rock guitar syllabuses at Grade 3 and in the acoustic guitar syllabus at Grade 5 and can be one of the more challenging aspects of both learning the guitar and teaching it.
You can use them for about 5 minutes once or twice a day outside of your guitar practice time. Few guitarists master barre chords quickly. It can take several weeks or months to master them and feel comfortable enough to switch between them.
A capo is also used to simplify some songs that would otherwise require barre chords. It doesn't work with all songs (for some, you simply have to learn barre chords) but for many tunes, a capo is a great option. They are not just for beginners, either.
You need to develop your strumming skills and you need to know plenty of chords. So if you've been struggling to master barre chords you should know this: it may be hard now, but it will definitely be worth it. Barre chords will make playing songs much, much easier.
Your thumb hurts because you are pushing your thumb backwards on itself in order to support your hand position on the neck. The only way forward is to practice bar chords as much as you can, and your thumb and hand will eventually become stronger. Hope this helps.
At first, you'll find that fingering barre chords is difficult and even painful. This is perfectly normal. Like with so many things, it just takes a little time and persistence to build enough strength and muscle memory in your barre finger to be able to play the chords without thinking or adjustment.
C chord (barred)
However, the barred C chord is one of the hardest guitar chords for beginners. Although it involves the same notes but is rearranged (in a different order), this chord is more challenging to play.
Are barre chords harder than power chords?
A power chord is but a fragment of a barre chord, but they are much easier to play than a barre chord. This allows you to quickly change chords, but they don't offer the harmonic quality found in a full bar chord.