What Causes Mild Pain In The Chest And Middle Of The Back?

i had been experiencing a small chest pain, in my left pectoral area the past few days. it would appear from time to time throughout the day without warning and unrelated to any activity. it was a general tightness, it did not cause shortness of breath, it was relatively minor, but disconcerting because i was immediately worried about my heart today, i have not had the issue but tonight, as the day has progressed, i have been bothered by a pain in my mid-back, both sides, but it is not as a result of any physical activity or any trauma to the area. both the chest and back have been accompanied by acid reflux and i am having trouble and pain attempting to bend over at the waist. the pain in the back does not appear to be muscle related per se, but it is preventing me from bending over, there is a general tightness, as if i had over-exerted or pulled a muscle but there is no activity which drove this pain or discomfort