Ouch, so sorry for the frustration and pain!

Yes, using a strap, and experimenting with your body-postion as it relates to the guitar is a great idea. You might even try (with a strap) playing standing up. Or, playing while supportin your body on a tall stool. Playing on a higher, or a lower, chair. Some folks like to riase one of their feet up, maybe using a yoga block or a box (4 - 6 inches or so?)

Not sure where you are at in terms of what you are studying here on GuitarTricks, and what you are learning with a teacher - but my Fundamentals 1 Course is designed to ease your hands into the kind of angles, stretch, and strength they need to play without pain.

Even if your skill level is beyond Fundamentals 1, you might visit the progression of lessons with the idea that it is designed to gently train and open up your hand and wrist muscles and joints.

One last thing - the size and condition of your guitar can make a huge difference. If the action is too high, you're having to work way too hard to play the chords. If the guitar is too big for your physical frame, it puts your shoulders and elbows and wrists into positions that may be contributing to your difficulties.

Find what you can play that does not cause pain (another plug for the super-easy stuff in Fundamentals 1), and stay with that for a while.

Nice and easy, nice and slow.

-Lisa