History:

A 44-year-old female presents with a current complaint of an exacerbation of chronic low back pain.  She reports that the pain typically worsens as the day progresses, is worse with prolonged static positioning (both sitting and standing), and with prolonged activity.  She complains of an intermittent feeling of stiffness or tightness and an intermittent sensation that she describes as “locking” in her spine.  She reports that she has utilized self-manipulation techniques that temporarily seem to alleviate her symptoms, but they do not seem to provide lasting relief.  She denies any acute trauma or injury and denies any numbness or tingling into the extremities. 

She reports a history of widespread joint pain that is intermittently worse in specific joints, and a history of migraines and GI issues.  She typically practices yoga 2-3 times per week and enjoys dancing but has been less active in the past several months due to her busy schedule.  She is on medications for anxiety, does not smoke or drink, and is a stay-at-home mother with 2 children. 

Question: Based on this clinical history, what are some differential diagnoses you are considering?