I get upper back pain especially around shoulder blades. it hurts more when moving & sometimes when taking a deep breath. i do carry my 3yr old a lot.?

Spine: Without a history of trauma, shoulder blade pain can be caused by poor posture, a bad disc in the spine, or an irritated nerve in the neck. See your doctor if this pain lasts greater than 2 weeks.

Subscapular bursitis: Little known problem in rheumatology and arthritis circles, but this is a likely diagnoses. You may have also sprained your rhomboids. But chest expansion will cause pain with the first diagnosis.