your symptoms sound like you have upper crossed syndrome-- it is an imbalance of the flexion muscles vs the extensor muscles of the thoracic area/chest/neck. it is postural. i'd bet you have some sort of desk job or spend alot of time hunching over a computer. what happens here is the chest muscles, the scalenes, the scms and upper traps get short and tight, and the muscles that support your scapulas in he back and the thoracic spine become weak and stfretched. a classic sign of this is mid back pain and chest muscle tightness and pain. the solution is to strengthen the mid back and do trigger point work/stretchig of the pecs, scalenes, scms and upper traps. Erik Dalton has a good website o this syndrome. Also do a search for Vladimir Janda who first identified this common and hardly ever diagnosed syndrome. Paul D'Arezzo has great book on posture. See a website by Jolie Bookspan. trigger point manual by Clair Davies.
ask your doctor (i see you have an appt tomorrow) if he ever even heard of this syndrome. He'll probably say no. he'll probably also send you for xrays, an MRI, EKG, bloodwork and all that stuff. EKG and bloodwork is non invasive, inexpensive and fine, but in my humble opinion (I am a dentist who lived (2 1/2 yrs) thru and fixed this exact problem) I believe your problem is muscular like I explained above, and your test results will most likely come back ok, unless there is somethng else wrong with you. These muscular imbalasnce syndromes do not show up on any lab tests--pills will do nothing. only you ca fix it.
you may benefit from the info I posted above. thoracic pain due to problems in the actual spine (like T herniations) is unusual becasue the T spine doesnt move that much due to the fact that it is connected to the rib cage. most thoracic back pain is due to weak mid back muscles (rhomboids, longitudinal spine muscles) that comes from being hunched and flexed and not extending the back and doing exercises to strengthen this area. Computer use is a killer.
That is totally weird, because I am also a 36 yr old female and for about a month (continually worsening) I have been waking in the night over and over with severe upper back pain on the left side. It is my body getting me to move to a new sleeping position and it will ease slightly (enough to go back to sleep) for a while and then wake me to move again. Mine started with a weird pressure in my chest, kinda like someone was sitting on it, and when I took a real deep breath my upper spine popped and then the pressure on my chest was relieved, this has happened several times. Then from there my left chest area (right above my breast) developed a deep ache during the day and at night it switches to radiating from my back. When I have the chest achiness, I can rub the muscles beside the shoulder blade in my back and it helps relieve my chest. I have no idea what is going on but I have a Dr. aptmt. tomorrow because at this point I am just sooooooooo tired! Between the bad sleep, the three kids and the pain I am EXHAUSTED!
You provide a lot of useful information about your condition. I would think that your discectomy is not related to your current problem. Your symptoms of pain after sleeping for 5-6 hours is a little odd. If your pain is throughout the day and worst at night, you are likely more sensitive to it when you are not doing anything else. If it is ONLY at night, that is somewhat odd. I don't know how long you have had these symptoms for, but if it has been several months and you are ONLY having upper back pain, an MRI of your thoracic spine is not a bad idea. Your symptoms don't sound like classic AS. You cite some other potential causes for your pain and that is also reasonable to pursue if there are no imaging abnormalities. I would also think of what else you have been doing lately or has changed in your life that might contribute to the pain and if you could curtail any of these activities to see if you improve.