Stretching is probably not going to help, at least on your own. But what you need is for someone, even with no experience, to knead your muscles as hard as you can take it. Leave your muscles in a relaxed position and don't clench them. Follow up with a hot soak (as hot as you can tolerate) in Epsom Salt.
Another alternative that I've gotten some relief from is our best friend, HAHA, needles! Trigger points (with lidocaine), acupuncture, and dry needling ALL release the tension that we just can't "stretch" out, and help the muscle relax. I hope some or all of this helps! I've been through the wringer with decades of "treatments!"