For most chords and for individual notes, I don't have to press very hard. I'm getting accustomed to the proper amount of pressure needed for that. It's when I go to barre across three to five strings, then put two or three fingers on two other strings for a chord, that I wind up in pain.
I have the guitar about at my stomach, not slung low. It's the best I can do to minimize the degree to which I have to bend my wrist. Trying to do the first few chords for "Brown Sugar" isn't easy. The first chord is barring (is that the right spelling?) strings #2, 3 and 4 at fret #12 with the index finger, then putting finger two on string #2 at fret 13 and and finger three on string 4 at fret 14.
The other difficult one is barring strings 2,3 and 4 at fret 1, and putting finger 2 on string 2 at fret 2, and finger 3 on string 4 at fret 3. The frets are so far apart, and it's down the neck so far, that I'm really contorting my wrist and hand.
I'm sure I don't have the finger strength to properly barre the strings.