I woke up with pain in my upper back - between the shoulder blades - and in my chest. The pain is worse when i turn my torso or neck. it feels best when i am sitting up in bed on one of my sides. my back pain worsens when i lay flat on my back. i usually sleep about 6-7 hours a night, but last night i slept for 9 and woke up much later than i usually do (at 1:30pm rather than 7:30-8am). im a 25 year old female, nonsmoker, irregularly exercise, eat relatively healthy. Ive had a history of mild GERD, and stopped taking birth control pills last week because it was causing my resting heart rate to increase. Any idea what is causing this pain?