My sternum keeps locking up, particularly when I m trying to do any kind of physical activity (playing with my 9 month old, etc). I ve been seeing a chiropractor weekly, but it keeps persisting. She suggested I stop/limit my physical strain, which is not possible with a 9 month old. My workload has increased quite a bit lately and carries a high stress factor in my life. I have a long history of anxiety and depression, which I ve been in active treatment for 3 years now... Could it be related? I want to fix the root of the problem, not the symptom.