This is the kind of pain that is surprising and will take your breath away.
The usual reaction to this kind of pain and just back pain in general is to stop using the muscles that hurt. If walking hurts, you sit; if sitting hurts, you lay.
This lack of motion might be all right for the first couple of days after a muscle strain or sprain, but it isn’t all right for the long term.
Exercise is an essential part of healing a muscle. Inactivity prolongs the healing process and will leave muscles weak.
Now, don’t misunderstand what I’m saying here. I am certainly NOT implying that you should start doing strenuous aerobic exercises.
I am saying that two days after the initial muscle strain, you do need to start doing some very controlled exercise of the muscles involved.
This muscle exercise should be in the form of stretching — not lifting, and never twisting.
Stretching exercises should be done in a very gradual and progressive way. Start slow, but start.
Exercise helps to provide nutrients to disc space and soft tissues in the back and to help keep discs, muscles, ligaments, and joints healthy. Lack of these nutrients will only slow or stop the healing process.
Exercising back muscles will not only promote healing. It will reduce the pain and possibly help to prevent future back muscle strains and sprains.
If you can, see a physical therapist for instructions and stretching exercises that will help to speed healing.
If you can’t see a physical therapist, see Google. By using Google and searching for exercise to reduce back pain, you will get a lot of hits.