You have tried doing the breathing exercise I recommended
Number One: Too big of a breath causes increased lower back pain. Yes, that can occur. Only due the breath that you can do without pain, this is not a contest. As your diaphragm gets stronger you will automatically feel that your breath increases without this pain.
Number Two: Abdominal scarring. This is one of my favorite reasons for your restrictions because this is where we come in. If this scar tissue is not directly mobilized, your breathing may never completely be restored to normal. Abdominal scarring can be like a spider web. It has multiple layers and can go in various directions. With functional manual therapy we can improve the ability of the muscles to move on each other and enhance the ability of the organs underneath to glide and slide on one another. Now here is the kicker, some of you may not even now it is a problem because you just have chronic lower back pain and have just been blaming those muscles for all of your pain.
So here is a way for you to know if your abdominal scar tissue is causing
So here is a way for you to know if your abdominal scar tissue is causing your pain, especially for lower abdominal scars (hysterectomy, C-section, inguinal hernia). Stand on one leg (holding onto a wall with your other hand) and then swing the other leg forward and back into a big range of motion. If you feel stiffness in you back or hips and it is painful, then it may be coming from that scar tissue.
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Another way, is to perform a Yoga Cobra Pose (see pic).
In this posture, see if you feel pulling in your abdomen. Does it change when you look over one shoulder or the other?
Go with your gut, if you can’t get that breath and you feel like there is a structural cause for it, than seek a functional manual physical therapist. SLOW DOWN ... Just Breathe!