(2) The pain may be exacterbated by inflammation, so NEVER use heat! Only col: icw cubes in a big ziploc bag folded in a towel.
(3) If the posture reliebing the muscle tension, and the cold for the inflammation, then also take a couple of ibuprofen, which is an anti-inflmmatory pain reliever to further diminish inflammation.
(4) One other device is a backboard which is like a teeter-tooter. You lay on the board with yoe heels fastened to it, and swing the heel end up and the head end down so that body weight pulls on the spine to lengthen it. Athletes use this a lot. You will see TV ads for a fancy one which wil work very well. But it can be done with a two-foot by eight-foot by 5/8 or 3/4 inch thick "plank', just (while laying down on it) roping the heels to the foot of the board, then lifting up the foot end and supporting that with a chair or step-ladder, with the head end still on the floor.
All these should relieve these hurting muscles enough for them to recuperate and get their strength back.
How I know about this is pretty obvious., eh?
Then to prevent it from reoccurring, go spend a few bucks on some twelve inch wide six-foot boards to place between her/your mattress and its supporting box springs (negating their curvature that they impart when you sleep on your side) so that your body is straight however you sleep, preferably ob your back.
Write me as to how this works when you have done it.