Stabbing pain under the left shoulder blade can limit your arm movement, affecting your daily activities. The shoulder blade is the triangular bone forming your upper back or shoulder. This interscapular pain can be sharp or stabbing, felt between the shoulder blade and the spine, or tender, affecting the entire upper back.
The common causes of stabbing pain under the left shoulder blade are poor posture, improper lifting techniques, overuse of shoulders, dislocated rib, or cardiovascular issues. This pain is not usually problematic and only requires a few at-home treatments to get better.